'Solve for y' means that you have to clear 'y' from the equation:

Clearing 'y':

Now, to find the value of 'y' for each value of 'x' you just have to replace 'x' in the expression above by each of the given values. This is:
For x = -1


When x = -1, y = 7.
For x = 0:


When x = 0, y = 5
For x = 3:


When x = 3, y = -1