Question

What is the answer?

Answer 1

`\begin{gathered} f(x)=3x-7 \\ \text{This means the function of x is given on the right hand side,} \\ \text{When it now becomes f(4), you substitute for x=4} \\ f(4)=3(4)-7 \\ f(4)=12-7 \\ f(4)=5 \end{gathered}`