Since (3/2 x) and (-1/2 x + 4) are both equal to the same thing,
they must be equal to each other.
So you can write 3/2 x = -1/2 x + 4 .
Use that equation to find the value of 'x'.
Then write that value in place of 'x' in either one
of the original equations to get 'y'.
Now you can solve it yourself, faster than I can write the solution here.