Question:
A function is defined as $f(x) = x^2 - 3x + 4$. What expression can be used to describe $f(2x)$? Express your answer in simplified form in terms of $x$.

Answer:
We have that
\[f(2x) = (2x)^2 - 3(2x) + 4 = \boxed{4x^2 - 6x + 4}.\]