Question

Find three solutions of the equation (x^2-9)(x^3-8)=0

Answer 1

(x^2-9)(x^3-8)=0

as you can see that (x^2-9) is in the form of a^2 - b^2 which equals (a+b)(a-b)

x^2 - 9
= (x)^2 -(3)^2
= (x+3)(x-3)


now, the equation becomes
(x+3)(x-3)(x^3-8)=0

(x+3) =0
x = -3


(x-3) = 0
x = 3

x^3 -8 = 0
x^3 = 8
x = cube rt. 8
= 2

so, the three solutions are -3, 3 and 2.