You're integrating with respect to y, you need to find the limits along the y axis. You're using the limits along the x-axis. Try integrating from 0 to 6.
How do I know to solve in terms of y or x?
So far I've tried it in terms of y and found the points of intersection to be -1, 5.. I tried evaluating the integral of , with the limits -1 to 5, but was marked incorrect... Any suggestions? Should it be in terms of x ?