Phân tích đa thức thành nhân tử:Phương pháp 2
49a^2-(2a-b)^2
(a-2b)^2-(3a+b)^2
(5a-b)^2-(2a+3b)^2
(4a+3b)^2-(b-2a)^2
25(x-3)^2-(2x-7)^2
Giúp mk vs
Phân tích đa thức thành nhân tử:Phương pháp 2
49a^2-(2a-b)^2
(a-2b)^2-(3a+b)^2
(5a-b)^2-(2a+3b)^2
(4a+3b)^2-(b-2a)^2
25(x-3)^2-(2x-7)^2
Giúp mk vs
`49a^2 -(2a-b)^2`
`=[7a-(2a-b)](7a+2a-b)`
`=(7a-2a+b)(9a-b)`
`=(5a+b)(9a-b)`
`(a-2b)^2 -(3a+b)^2`
`=[a-2b-(3a+b)](a-2b+3a+b)`
`=(a-2b-3a-b)(4a-b)`
`=(-2a-3b)(4a-b)`
`(5a-b)^2 -(2a+3b)^2`
`=(5a-b+2a+3b)[5a-b-(2a+3b)]`
`=(7a+2b)(5a-b-2a-3b)`
`=(7a+2b)(3a-4b)`
`(4a+3b)^2 -(b-2a)^2`
`=(4a+3b+b-2a)[4a+3b-(b-2a)]`
`=(2a+4b)(4a+3b-b+2a)`
`=2(a+2b)(6a+2b)`
`=2(a+2b)2(3a+b)`
`=4(a+2b)(3a+b)`
`25(x-3)^2 -(2x-7)^2`
`=[5(x-3)+2x-7][5(x-3)-(2x-7)]`
`=(5x-15+2x-7)(5x-15-2x+7)`
`=(7x-22)(3x-8)`
chúc học tốt
49a²-(2a-b)²
= (7a)²-(2a-b)²
= (7a-2a+b)(7a+2a-b)
= (5a+b)(9a-b)
(a-2b)²-(3a+b)²
=(a-2b-3a-b)(a-2b+3a+b)
= (-2a-3b)(4a-b)
(5a-b)²-(2a+3b)²
= (5a-b-2a-3b)(5a-b+2a+3b)
= (3a-4b)(7a+2b)
(4a+3b)²-(b-2a)²
= (4a+3b-b+2a)(4a+3b+b-2a)
= (6a+2b)(2a+4b)
25(x-3)²-(2x-7)²
= [5(x-3)]²-(2x-7)²
= (5x-15-2x+7)(5x-15+2x-7)
= (3x-8)(7x-22)