Solution:
Given:
[tex]f(x)=2x^2-4[/tex]
To find f(5x), this means the value of f(x) when x = 5x
Hence,
[tex]\begin{gathered} f(x)=2x^2-4 \\ f(5x)=2(5x)^2-4 \\ f(5x)=2(25x^2)-4 \\ f(5x)=50x^2-4 \end{gathered}[/tex]
Therefore,
[tex]f(5x)=50x^{2}-4[/tex]
