Verified answer

Ответ:

7) 9+12x+4x^2=(3+2x)^2

8) (3x+1)(4x-2)-6(2x-1)^2+14=12x^2-6x+4x-2-6(4x^2-4x+1)+14=12x^2-6x+4x-2-24x^2+24-6+14=-12x^2+22x+6