(3 - х² )² - (5 - х² )² = 0 Помогите

Question

(3 - х² )² - (5 - х² )² = 0
Помогите

Answer 1

(3 - x^2 - 5 + x^2)(3 - x^2 + 5 - x^2) = 0
 - 2 (- 2x^2 + 8) = 0  /: - 2
- 2x^2 + 8 = 0   /: - 2
x^2 - 4 = 0
x^2 = 4
x = ± √4
x = ± 2 

Answer 2

(3 - х² )² - (5 - х² )² = 0
(3-x²-5+x²)(3-x²+5-x²)=0
-2*(-2x²+8)=0
-2x²+8=0
2x²=8
x²=4
x=-2 U x=2