Question

If f(x) = 2x^2 - 5 and g(x) = 2x + 1, evaluate f(g(x)) when x = -3

Answer 1

$f(x)=2x^2-5$

$g(x)=2x+1$

$f[g(x)]=f(2x+1)=2(2x+1)^2-5$

when x = -3

$\begin{gathered} \Rightarrow[2(2\times-3+1)^2]-5 \\ 2[-5]^2-5=45 \end{gathered}$

The final answer is 45