Yes you got them all correct at least I think.
X+y=8
2x^2-y=-5
elimination method means you link the 2 equations together to make one
these two already have y in the perfect form where you can cancel it out +y and -y so no need to perform any other action to a certain equation.. all you need to do is add them now
2x^2+x=3
So the since the length of the longer side is 45inches we know that the longer table is 5 times as larger than the small desktop. And we know 6 x 5 = 30.
So 45x30= 1,350 so the answer is 1,350 square inches! :)