1. $ 8x + 7x - 36:12=-33 $
$⇒ 8x+7x-3=-33$
$⇒ 8x+7x=-33+3$
$⇒ 15x=-30$
$⇒ x=-30:15$
$⇒ x=-2$
Vậy $x=-2$
2. $ 86: [2. (2x - 1)^2 – 7] + 16 = 2.9 $
$⇒ 86: [2. (2x - 1)^2 – 7] + 16=18$
$⇒ 86: [2. (2x - 1)^2 – 7] =18-16$
$⇒ 86: [2. (2x - 1)^2 – 7] =2$
$⇒ 2. (2x - 1)^2 – 7 =86 : 2$
$⇒ 2. (2x - 1)^2 – 7 =43$
$⇒ 2. (2x - 1)^2 =43+7$
$⇒ 2. (2x - 1)^2 =50$
$⇒ (2x - 1)^2 =50:2$
$⇒ (2x - 1)^2 =25$
$⇒ (2x - 1)^2 =5^2$
$⇒ 2x - 1 =5$
$⇒ 2x =5+1$
$⇒ 2x =6$
$⇒ x =3$
Vậy $x=3$
