how do you solve this ?

When given a value of the variable, we replace each instance of the variable in the problem with that number. In this case, the expression becomes:
[tex] \frac{3^2 + 3}{3 - 1} [/tex]
After this, we merely need to simplify the answer.
[tex] \frac{9 + 3}{3 - 1} [/tex]
[tex] \frac{12}{2} [/tex]
Simplifying 12/2 gives us the answer 6.