Firstly, you know you made a mistake when you get a negative area.
You have to know the limits therefore you must calculate the intersections betwen the two curves.
From this quatdration equation you can deduce using the Wiet's rule for quadratic formulae that intersections are x= -4 and x=2 which are now the limits.
Then you integrate each of the equations with respect to x from -4 to 2.
When you get the two results for integrals you must (!) take the absolute value for the difference between them. Then you will obtain positive value and true anwser.