To determine the value of f(-1), we substitute -1 to the x variable of the function given. We do as follows:
f(x)=12/4x+2
f(-1) = 12/ 4(-1) +2
f(-1) = -3 + 2 = -1
It seems that the answer is not one of the choices. Nevertheless, the process will be the same for different set of equations.
