Question

Simplify:(x^2 – 5)(x+ 5) + 25 = 0

Answer 1

x^3 + 5 x^2 - 5 x - 25  + 25 = 0

x^3 + 5 x^2 - 5 x = 0

x ( x^2 + 5 x - 5) = 0

x = 0  or    x^2 + 5x - 5 = 0
                x = [-5 +- 3√5 ]/2

Answer 2

(x^2 -5)(x + 5) + 25 = 0

x^3 + 5x^2 -5x -25 +25 =0

x^3 +5x^2 -5x =0

x(x^2 +5x -5) =0

x =0. & x^2 +5x -5 =0

x^2 +5x -5 =0
use quadratic formula,

x = { -5 +_√45}/2

hence,

x = 0, ( -5+√45)/2. and (-5 -√45)/2