Question

if f(x) is a quadractic expression how to find f^-1(x)

Answer 1

You can find the inverse of any quadratic function by using completion of squares method.

For eg.

Let f(x)=x²+2x+30

y=x²+2x+3

y=x²+2x+3+1-1

y=x²+2x+1+2

y-2=(x+1)²

$\sqrt{y+2}$=x+1

x=$\sqrt{y+2}$-1

So, f⁻¹(x)=$\sqrt{y+2}$-1