Who want to talk. I am bored.

Pls! does anybody know a shortcut for answering these types of questions in the future?

Mat bought a phone for $100. he has to pay $30 per mouth. if he has paid $640 in total, how many mouth has he had the phone?

50 plz, given the system of equations, match the following items. x + 3 y = 5 x - 3 y = -1 a) x-determinant b) y-determinant c) system determinant match the following to the pictures below.