(x+2)(x ^2-2x+4)-x(x+2)(x-2)=12
(x+2)*(x^2-2x+4-x*(x-2))=12 (x+2)*(x^2+4-x^2+2x)=12 (x+2)*4=12 4x+8=12 4x=12-8 4x=4 x=1