Question

х в кубе +5хв квадрате = 4х+20

Answer 1

x^3+5x^2=4x+20
x^3+5x^2-4x-20=0
x^2(x+5)-4(x+5)=0
(x^2-4)(x+5)=0
(x-2)(x+2)(x+5)=0
x1=2
x2=-2
x3=-5