Question

Factorise:
$x ^{4} + 5 {x}^{2} + 9$
​

Answer 1

X⁴+5x²+9

=(x²)²+(3)²+2×3×x²-x²

=(x²+3)²-x² (a+b)²=a²+b²+2ab

Ans=(x²+3)²-x²