Find the common ratio of the geometric sequence-15,-30,-60

Find the x-intercept and y-intercept of the line. 3x + 5y = −15

David must install fencing around a lot that is shaped like a right angle.the side of lot that runs east-west is 200 ft long.the side of the lot runs north-south is 125 ft long.calculate how many feet of fencing he will need to surround the entire lot.

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