(2x-3)x(3x+2)-(2x-5)x(5x+2) (3x-7)^2-(7x-3)^2

Đáp án:

Ta có : 

`(2x – 3)(3x + 2) – (2x – 5)(5x + 2)`

` = 6x^2 – 9x + 4x – 6 – 10x^2 + 25x – 4x + 10`

` = -4x^2 + 16x + 4` 

`(3x – 7)^2 – (7x – 3)^2`

` = (3x – 7 – 7x + 3)(3x – 7 + 7x – 3)`

` = (-4x – 4)(10x – 10)`

` = -4.(x + 1).10.(x – 1)`

` = -40.(x + 1)(x – 1)`

` = -40.(x^2 – 1)`

` = -40x^2 + 40`

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