Evaluating a function means finding the value of the function that corresponds to a given value of x. To do this, simply replace all the x variables with whatever x has been assigned.
We want to evaluate x = - 1 on the function
[tex]f(x)=7(9-2)-4[/tex]Since the function doesn't depend on x, the function evaluated at x = - 1 will be
[tex]f(-1)=7(9-2)-4=7(7)-4=49-4=45[/tex]