Q1: Find the intersection of 2P=4Q-10 and P= -Q+10.

A1: Dividing both sides of the first equation by 2 we find that P=2Q-5. Since at the intersection the P is the same for both equations we can set 2Q-5=-Q+10, which is 3Q=15 or Q=5. Plugging this back into either of the two original equations we find that 5=-Q+10 or -Q=-5 or Q=5.

Q2: Calculate ¶/¶y
x^{3}y^{2}+7xy^{3}+3x+4y+7

A2: 2x^{3}y+21xy^{2}+4