Question

x la pătrat + x la cub = - 18

Answer 1

$\it x^2+x^3=-18\\ \\ (-3)^2+(-3)^3=-18$

Answer 2

x²+x³=-18

x³+x²=-18

x³+x²-(-18)=-18-(-18)

x³+x²+18=0

(x+3)(x²-2x+6)=0

x+3=0

x²-2x+6=0

=>x=-3