Question

Tìm x biết:

(x-3).(x+5)- (x-4)(x+7)+2x = 11

giúp mk vs mk đang cần gấp plsssssss

Answer 1

\(\Leftrightarrow x^2+2x-15-\left(x^2+3x-28\right)+2x=11\)

\(\Leftrightarrow x^2+4x-15-x^2-3x+28=11\)

=>x+13=11

hay x=-2

Answer 2

`(x-3).(x+5)- (x-4)(x+7)+2x = 11`

`x^2 +2x-15 - x^2 -3x+28+2x=11`

`(2x-3x+2x)+(-15+28)=11`

`x +13=11`

`x=11-13`

`x=-2`

Vậy `x=-2``