Find the real or imaginary solutions of each equation by factoring

Sum of  2 perfect cubes
a³+b³=(a+b)(x²-xy+y²)
so

x³+4³=(x+4)(x²-4x+16)
set each to zero
x+4=0
x=-4

the other one can't be solveed using conventional means
use quadratic formula
for
ax^2+bx+c=0
x=
for x²-4x+16=0
x=
x=
x=
x=
x=
x=

the roots are
x=-4 and 2+2i√3 and 2-2i√3

A: 0.26 would be the answer