for #1.

get the intersection points or graph them both to find them, if you graph them check which function is higher and integrate that one minus the other one in the range of the intersection points...

if you don't graph the functions, then after you get the intersection points (equal one function to the other and solve for x), evaluate both functions somewhere inside the intersection points and whichever functions gets a larger value it's higher...

i did it quickly and the intersection points are: at 0, 4 and 6

if you graph them you'll notice how they behave, if not, check again for which function is higher between the second set of intersection points...

I hope this wasn't too complicated