x^3+2x^2-5x+2=0
x^3-1+2x^2-5x+3=0
(x-1)(x^2+x+1)+(2x-3)(x-1)=0
(x-1)(x^2+x+1+2x-3)=0
(x-1)(x^2+3x-2)=0
(x-1)(x^2+3x+9/4-9/4-2)=0
(x-1)[(x+3/2)^2-17/4]=0
(x-1)(x+3/2-√17/2)(x+3/2+√17/2)=0
x=1或x=√17/2-3/2或x=-√17/2-3/2