semi colon problems

[ribspreader]

can some one explain the semi colon and solve this problem

f(x)=8x - 7 ;4

 

[mmm4444bot]

What do the instructions say?

 

[HallsofIvy]

I strongly suspect that there is more to the problem. That is, that there is first part that says "For these problems, evaluate the given function at the given value of x". In that case f is the given function and the number after the semicolon is the given value of x.