Dell Inspiron 14 5410 2in1 (70270653) | Core i5 - 1135G7 | 8GB | 512GB SSD | 14" FHD IPS - Touch | Win11 - Office | Finger | LED KEY | Bạc | 0222F

20,799,000

Giá trước đây: 23,990,000 - Tiết kiệm 13%

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)
Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)
Hard Disk: 512GB PCIe® NVMe™ M.2 SSD
VGA: Integrated Intel Iris Xe Graphics
Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display
Weight: 1,60Kg
Bảo hành: 12 tháng
VAT: Đã bao gồm VAT

ĐẶT HÀNG

Hướng dẫn
mua hàng

MUA TRẢ GÓP

Hướng dẫn
mua trả góp

Túi máy tính xách tay chuyên dụng

Giao hàng tận nơi

Thanh toán khi nhận hàng

Đổi trả trong 5 ngày
Không được đổi trả với lý do "không vừa ý"

12 tháng bằng hóa đơn mua hàng

Bảo hành chính hãng toàn quốc
Hotline: 19002074

Giới thiệu Thông số kỹ thuật Bình luận

CPU	11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)
Memory	8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)
Hard Disk	512GB PCIe® NVMe™ M.2 SSD
VGA	Integrated Intel Iris Xe Graphics
Display	14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display
Driver	none
Other	Fingerprint Reader, Backlit Keyboard, USB 3.1 Gen 1 Type A Ports, USB 3.2 Gen 2 Type C Port with Power Delivery + DisplayPort, Headphone and Microphone Combo, HDMI 1.4a Port, Micro SD Reader, 720p at 30 fps, HD RGB Camera Dual-Array Microphones, Stero Speakers with Realtek
Wireless	Intel Wi Fi 6 (802.11ax) + Bluetooth 5.1
Battery	3Cell 41Wh
Weight	1,60Kg
SoftWare	WINDOWS 11 HOME 64 SL + Office
Xuất xứ	Brand New 100%, Hàng Phân Phối Chính Hãng, Bảo Hành Toàn Quốc Tận nhà
Màu sắc	Silver
Bảo hành	12 tháng
VAT	Đã bao gồm VAT

Load thêm bình luận

Gửi bình luận

Họ tên

Số ĐT

Nội dung

Bạn đã xem

LCD Acer K222HQL (WX2SS.004) | 21.5 inch Full HD (1920 x 1080) @ 60Hz with LED Backlight _Anti Glare _VGA _DVI _719D

2,200,000 2,400,000

Dell Inspiron 14 5410 2in1 (70270653) | Core i5 - 1135G7 | 8GB | 512GB SSD | 14" FHD IPS - Touch | Win11 - Office | Finger | LED KEY | Bạc | 0222F

20,799,000 23,990,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Lenovo ThinkPad X13s Gen 1 (21BX0017VN) | Qualcomm Snapdragon 8cx Gen 3 | 16GB | 512GB SSD PCIe Gen 4 | 13.3 inch WUXGA IPS | Win 11 Pro | IR Camera | Finger | LED KEY | 0922A

29,199,000 36,890,000

CPU: Qualcomm Snapdragon 8cx Gen 3 (8C, 4x Kryo Prime + 4x Kryo Gold @3.0GHz)

Memory: 16GB Soldered LPDDR4x-4266

HDD: 512GB SSD M.2 2242 PCIe 4.0x4 NVMe Opal2

VGA: Integrated Qualcomm Adreno 690 GPU

Display: 13.3 inch WUXGA (1920x1200) IPS 300nits Anti-glare

Weight: 1,05 Kg

Dell Inspiron 5410 (P143G001BSL) | Intel® Tiger Lake Core™ i5 _ 11320H | 8GB | 512GB SSD PCIe | VGA INTEL | Win 11 _ Office Home & Student 2021 | 14 inch Full HD | Finger | LED KEY | 0122S

20,799,000 24,990,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 14 2 in 1 5410 (J42F82) | Intel® Tiger Lake Core™ i7 _ 1195G7 | 16GB | 512GB SSD PCIe | GeForce® MX350 with 2GB GDDR5 | Win 11 _ Office Home & Student | 14 inch Full HD IPS Touch Screen | Finger | LED KEY | 0122D

29,799,000 33,990,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 3515 (G6GR72) | AMD Ryzen™ 5 3450U | 8GB | 256GB SSD PCIe | Radeon™ Graphics Vega | Win 11 _ Office Home & Student | 15.6 inch Full HD | 0122D

12,299,000 19,490,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 3515 (G6GR71) | AMD Ryzen™ 3 3250U | 8GB | 256GB SSD PCIe | Radeon™ Graphics Vega | Win 11 _ Office Home & Student | 15.6 inch Full HD | 0122D

10,799,000 14,990,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 3511 (70270650) | Intel® Tiger Lake Core™ i5 _ 1135G7 | 8GB | 512GB SSD PCIe | GeForce® MX350 with 2GB GDDR5 | 15.6 inch Full HD | Win 11 _ Office Home & Student 2021 | 0222F

16,999,000 22,990,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 3511 (P112F001CBL) | Intel Core i3 _ 1115G4 | 4GB | 256GB SSD PCIe | VGA INTEL | Win 11 - Office HS 2021 | 15.6 inch Full HD | 1021S | KMT8

11,299,000 17,290,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 5510 (0WT8R2) | Intel® Tiger Lake Core™ i5 _ 11320H | 8GB | 256GB SSD PCIe | VGA Intel® Iris® Xe | 15.6 inch Full HD | Win 10 _ Office Home & Student 2019 | Finger | LED KEY | 1021D | CT05

17,899,000 23,890,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 3501 (70234075) | Core i7 _ 1165G7 | 16GB | 512GB SSD PCIe | MX330 with 2GB GDDR5 | Win 10 | Full HD | 250NC

27,999,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 5510 (0WT8R1) | Intel® Tiger Lake Core™ i5 _ 11300H | 8GB | 256GB SSD PCIe | VGA Intel® Iris® Xe | 15.6 inch Full HD | Win 10 _ Office Home & Student 2019 | Finger | LED KEY | 1021D

21,299,000 23,390,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 3501 (70253898) | Intel® Tiger Lake Core™ i7 _ 1165G7 | 8GB | 512GB SSD PCIe | GeForce® MX330 with 2GB GDDR5 | Win 10 _ Office Home & Student 2019 | 15.6 inch Full HD | 1021F

23,499,000 24,590,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 3511 (P112F001ABL) | Intel® Tiger Lake Core™ i3 _ 1115G4 | 4GB | 256GB SSD PCIe | VGA INTEL | Win 10 _ Office Home & Student 2019 | 15.6 inch Full HD | 1021S | KMT8

11,499,000 16,890,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Dell Inspiron 3511 (P112F001BBL) | Intel® Tiger Lake Core™ i5 _ 1135G7 | 4GB | 512GB SSD PCIe | Intel® Iris® Xe Graphics | Win 10 _ Office Home & Student 2019 | 15.6 inch Full HD | 1021S

15,199,000 21,990,000

CPU: 11th Generation Intel® Tiger Lake Core™ i5 _ 1135G7 Processor (2.40 GHz, 8M Cache, Up to 4.20 GHz)

Memory: 8GB DDr4 Bus 3200Mhz (2 Slot, 4GB x 02)

HDD: 512GB PCIe® NVMe™ M.2 SSD

VGA: Integrated Intel Iris Xe Graphics

Display: 14 inch Full HD (1920 x 1080) Truelife IPS Touch Screen Narrow Border WVA Display

Weight: 1,60Kg

Mua ở đâu Tìm hệ thống cửa hàng

Positive SSL

HCM:	028.223.55555
HÀ NỘI:	024.2200.5555
ĐÀ NẴNG:	0236.656.9999
DEALER:	028.66889888
TRẢ GÓP:	028.2211.2232
HOTLINE:	1900.2074

Dell Inspiron 14 5410 2in1 (70270653) | Core i5 - 1135G7 | 8GB | 512GB SSD | 14" FHD IPS - Touch | Win11 - Office | Finger | LED KEY | Bạc | 0222F

LCD Acer K222HQL (WX2SS.004) | 21.5 inch Full HD (1920 x 1080) @ 60Hz with LED Backlight _Anti Glare _VGA _DVI _719D

Dell Inspiron 14 5410 2in1 (70270653) | Core i5 - 1135G7 | 8GB | 512GB SSD | 14" FHD IPS - Touch | Win11 - Office | Finger | LED KEY | Bạc | 0222F

Lenovo ThinkPad X13s Gen 1 (21BX0017VN) | Qualcomm Snapdragon 8cx Gen 3 | 16GB | 512GB SSD PCIe Gen 4 | 13.3 inch WUXGA IPS | Win 11 Pro | IR Camera | Finger | LED KEY | 0922A

Dell Inspiron 5410 (P143G001BSL) | Intel® Tiger Lake Core™ i5 _ 11320H | 8GB | 512GB SSD PCIe | VGA INTEL | Win 11 _ Office Home & Student 2021 | 14 inch Full HD | Finger | LED KEY | 0122S

Dell Inspiron 14 2 in 1 5410 (J42F82) | Intel® Tiger Lake Core™ i7 _ 1195G7 | 16GB | 512GB SSD PCIe | GeForce® MX350 with 2GB GDDR5 | Win 11 _ Office Home & Student | 14 inch Full HD IPS Touch Screen | Finger | LED KEY | 0122D

Dell Inspiron 3515 (G6GR72) | AMD Ryzen™ 5 3450U | 8GB | 256GB SSD PCIe | Radeon™ Graphics Vega | Win 11 _ Office Home & Student | 15.6 inch Full HD | 0122D

Dell Inspiron 3515 (G6GR71) | AMD Ryzen™ 3 3250U | 8GB | 256GB SSD PCIe | Radeon™ Graphics Vega | Win 11 _ Office Home & Student | 15.6 inch Full HD | 0122D

Dell Inspiron 3511 (70270650) | Intel® Tiger Lake Core™ i5 _ 1135G7 | 8GB | 512GB SSD PCIe | GeForce® MX350 with 2GB GDDR5 | 15.6 inch Full HD | Win 11 _ Office Home & Student 2021 | 0222F

Dell Inspiron 3511 (P112F001CBL) | Intel Core i3 _ 1115G4 | 4GB | 256GB SSD PCIe | VGA INTEL | Win 11 - Office HS 2021 | 15.6 inch Full HD | 1021S | KMT8

Dell Inspiron 5510 (0WT8R2) | Intel® Tiger Lake Core™ i5 _ 11320H | 8GB | 256GB SSD PCIe | VGA Intel® Iris® Xe | 15.6 inch Full HD | Win 10 _ Office Home & Student 2019 | Finger | LED KEY | 1021D | CT05

Dell Inspiron 3501 (70234075) | Core i7 _ 1165G7 | 16GB | 512GB SSD PCIe | MX330 with 2GB GDDR5 | Win 10 | Full HD | 250NC

Dell Inspiron 5510 (0WT8R1) | Intel® Tiger Lake Core™ i5 _ 11300H | 8GB | 256GB SSD PCIe | VGA Intel® Iris® Xe | 15.6 inch Full HD | Win 10 _ Office Home & Student 2019 | Finger | LED KEY | 1021D

Dell Inspiron 3501 (70253898) | Intel® Tiger Lake Core™ i7 _ 1165G7 | 8GB | 512GB SSD PCIe | GeForce® MX330 with 2GB GDDR5 | Win 10 _ Office Home & Student 2019 | 15.6 inch Full HD | 1021F

Dell Inspiron 3511 (P112F001ABL) | Intel® Tiger Lake Core™ i3 _ 1115G4 | 4GB | 256GB SSD PCIe | VGA INTEL | Win 10 _ Office Home & Student 2019 | 15.6 inch Full HD | 1021S | KMT8

Dell Inspiron 3511 (P112F001BBL) | Intel® Tiger Lake Core™ i5 _ 1135G7 | 4GB | 512GB SSD PCIe | Intel® Iris® Xe Graphics | Win 10 _ Office Home & Student 2019 | 15.6 inch Full HD | 1021S

Thông tin công ty

Hỗ trợ khách hàng

Tin tức

Tổng đài hỗ trợ

Dịch vụ thanh toán hộ

Hãng sản xuất

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Hãng sản xuất

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Hãng sản xuất

Dòng sản phẩm

Hãng sản xuất

Hãng sản xuất

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Hãng sản xuất

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Hãng sản xuất

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Hãng sản xuất

Dòng sản phẩm

Dòng sản phẩm

Hãng sản xuất

Dòng sản phẩm

Hãng sản xuất

Dòng sản phẩm

Dòng sản phẩm

Dòng sản phẩm

Hãng sản xuất

Hãng sản xuất

Dòng sản phẩm

Dòng sản phẩm

Hãng sản xuất

Hãng sản xuất

Hãng sản xuất

Hãng sản xuất

Hãng sản xuất

Dòng sản phẩm

Dell Inspiron 14 5410 2in1 (70270653) | Core i5 - 1135G7 | 8GB | 512GB SSD | 14" FHD IPS - Touch | Win11 - Office | Finger | LED KEY | Bạc | 0222F

LCD Acer K222HQL (WX2SS.004) | 21.5 inch Full HD (1920 x 1080) @ 60Hz with LED Backlight _Anti Glare _VGA _DVI _719D

Dell Inspiron 14 5410 2in1 (70270653) | Core i5 - 1135G7 | 8GB | 512GB SSD | 14" FHD IPS - Touch | Win11 - Office | Finger | LED KEY | Bạc | 0222F

Lenovo ThinkPad X13s Gen 1 (21BX0017VN) | Qualcomm Snapdragon 8cx Gen 3 | 16GB | 512GB SSD PCIe Gen 4 | 13.3 inch WUXGA IPS | Win 11 Pro | IR Camera | Finger | LED KEY | 0922A

Dell Inspiron 5410 (P143G001BSL) | Intel® Tiger Lake Core™ i5 _ 11320H | 8GB | 512GB SSD PCIe | VGA INTEL | Win 11 _ Office Home & Student 2021 | 14 inch Full HD | Finger | LED KEY | 0122S

Dell Inspiron 14 2 in 1 5410 (J42F82) | Intel® Tiger Lake Core™ i7 _ 1195G7 | 16GB | 512GB SSD PCIe | GeForce® MX350 with 2GB GDDR5 | Win 11 _ Office Home & Student | 14 inch Full HD IPS Touch Screen | Finger | LED KEY | 0122D

Dell Inspiron 3515 (G6GR72) | AMD Ryzen™ 5 3450U | 8GB | 256GB SSD PCIe | Radeon™ Graphics Vega | Win 11 _ Office Home & Student | 15.6 inch Full HD | 0122D

Dell Inspiron 3515 (G6GR71) | AMD Ryzen™ 3 3250U | 8GB | 256GB SSD PCIe | Radeon™ Graphics Vega | Win 11 _ Office Home & Student | 15.6 inch Full HD | 0122D

Dell Inspiron 3511 (70270650) | Intel® Tiger Lake Core™ i5 _ 1135G7 | 8GB | 512GB SSD PCIe | GeForce® MX350 with 2GB GDDR5 | 15.6 inch Full HD | Win 11 _ Office Home & Student 2021 | 0222F

Dell Inspiron 3511 (P112F001CBL) | Intel Core i3 _ 1115G4 | 4GB | 256GB SSD PCIe | VGA INTEL | Win 11 - Office HS 2021 | 15.6 inch Full HD | 1021S | KMT8

Dell Inspiron 5510 (0WT8R2) | Intel® Tiger Lake Core™ i5 _ 11320H | 8GB | 256GB SSD PCIe | VGA Intel® Iris® Xe | 15.6 inch Full HD | Win 10 _ Office Home & Student 2019 | Finger | LED KEY | 1021D | CT05

Dell Inspiron 3501 (70234075) | Core i7 _ 1165G7 | 16GB | 512GB SSD PCIe | MX330 with 2GB GDDR5 | Win 10 | Full HD | 250NC

Dell Inspiron 5510 (0WT8R1) | Intel® Tiger Lake Core™ i5 _ 11300H | 8GB | 256GB SSD PCIe | VGA Intel® Iris® Xe | 15.6 inch Full HD | Win 10 _ Office Home & Student 2019 | Finger | LED KEY | 1021D

Dell Inspiron 3501 (70253898) | Intel® Tiger Lake Core™ i7 _ 1165G7 | 8GB | 512GB SSD PCIe | GeForce® MX330 with 2GB GDDR5 | Win 10 _ Office Home & Student 2019 | 15.6 inch Full HD | 1021F

Dell Inspiron 3511 (P112F001ABL) | Intel® Tiger Lake Core™ i3 _ 1115G4 | 4GB | 256GB SSD PCIe | VGA INTEL | Win 10 _ Office Home & Student 2019 | 15.6 inch Full HD | 1021S | KMT8

Dell Inspiron 3511 (P112F001BBL) | Intel® Tiger Lake Core™ i5 _ 1135G7 | 4GB | 512GB SSD PCIe | Intel® Iris® Xe Graphics | Win 10 _ Office Home & Student 2019 | 15.6 inch Full HD | 1021S

Thông tin công ty

Hỗ trợ khách hàng

Tin tức

Tổng đài hỗ trợ