Question

(x2 –2x+4)(x+2)+(x–2)(x2 +2x+4)

Answer 1

Factorizar: 
(x^2 + 2x - 4)(x - 2) = [x + 1 - (5)^1/2][x + 1 + (5)^1/2](x - 2) 

Despejar ó sacar las raíces de "x": 
(x^2 + 2x - 4)(x - 2) = 0 
[x - (5)^1/2][x + (5)^1/2](x - 2) = 0 
x1 = 2 
x2 = -1 + (5)^1/2 
x3 = -1 - (5)^1/2 

Multiplicación: 
(x^2 + 2x - 4)(x - 2) = x^3 - 2x^2 + 2x^2 - 4x - 4x + 8 = x^3 - 8x + 8