7x= 2*3*x*g
7=6g
g=7/6
(7/6)²+7x+9x²= (7/6+3x)²
<span>(x-2)(3x+4)-3(x+1)^2=</span>3x^2-2x-8-3x^2-6x-3=-8x-11
Решение во вложении...