Question

how do you solve f(2)=7x^2-4x

Answer 1

\[\Large f(\color{#3366CF}{x})=7(\color{#3366CF}{x})^2-4(\color{#3366CF}{x})\]
Plugging in x=2 gives us,\[\Large f(\color{#3366CF}{2})=7(\color{#3366CF}{2})^2-4(\color{#3366CF}{2})\]

Understand how to solve it from there?