2) (x²-4x+4)(x-3)=20x-40
x³-3x²-4x²+12x+4x-12-20x+40=0
x³-7x²-4x+28=0
(x³-7x²)-(4x-28)=0
x²(x-7)-4(x-7)=0
(x²-4)(x-7)=0
(x-2)(x+2)(x-7)=0
x=2 x=-2 x=7
<span>(3а+4)^2=9a^2 +24a+16</span>
в=4