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
(x-2)(x-3) = 20
x^2 - 3x - 2x + 6 - 20 = 0
x^2 - 5x - 14 = 0
D = 25 + 56 = 81
x1 = (5 + 9)/2 = 7
x2 = (5 - 9)/2 = -2
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