Question

Solve the quadratic in form equation x^4-14x^2+45=0

Answer 1

x⁴-14x²+45=0
(x²) ²-14x²+45=0
let y=x²
y²-14y+45=0
(y-9) (y-5) =0
y=9 or y=5
x²=9 or x²=5
x=±3 or x=±√5