Решите уравнения

1) 5x^3-15x^2-x+3=0

2) x^3-2x^2+x = (x^2-2x+1) ^2

1) x (5x^2 - 15x-1) + 3 = 0

x (5x^2 - 15x-1) = - 3

x = - 3 или 5x^2 - 15x-1 = - 3

5x^2-15x+2 = 0

D = (-15) ^2 - 4*5*2 = 225 - 80 = 145 (√D = √145 ≈ 12)

x1 = (15 + 12) / 2*5 = 27/10 = 2,7

x2 = (15-12) / 2*5 = 3/10 = 0,3

Ответ: x = - 3; 0,3; 2,7