Is w =15z direct variation

Find the solution of this system of equation -7x+y=-20 9x-3y=36

Compare the following pair of numbers a and b in three ways. a. find the ratio of a to b. b. find the ratio of b to a. c. complete the sentence: a is percent of b. a=120 and b=340 a. the ratio of a to b is . b. the ratio of b to a is . c. a is nothing percent of b.

How can constraints be used to model a real-world situation?