Question

Tìm x,biết :

 

Answer 1

$⇔ 4x^2 + 12x - x - 3 - 4x^2 + 2x - 6x + 3 = 13$
$⇔ 7x = 13$

$⇔ x = \dfrac{13}{7}$

Answer 2

`(4x-1).(x+3)-(2x+3).(2x-1)=13`

`<=>4x^2 +11x-3 - 4x^2 -4x+3=13`

`<=>(4x^2-4x^2)+(11x-4x)+(-3+3)=13`

`<=>7x=13`

`=> x=13:7`

`x=13/7`