True or false? when n is a negative interfere, n-n =0

Acoin bank containing only dimes and quarters has 12 more dimes than quarters. the total value of the coins is $11. how many quarters and dimes are in the coin bank?

Acourt reporter is transcribing an accident report from germany. the report states that the driver was traveling 80 kilometers per hour. how many miles per hour was the driver traveling?

Write an equation of the line that passes through the point (2, 3) and is perpendicular to the line x = -1. a) y = 1 b) y = 3 c) y = 0 eliminate d) y = -3