7.AT.C.9: Use variables to represent quantities and write and solve inequalities to model and reason about constraints and conditions in context. a. Write inequalities of the form px + q > r or px + q < r, where p, q, and r are specific rational numbers. b. Solve inequalities of these forms and graph the solution set on a number line. c. Interpret the solution set in terms of the context by describing what values are possible or reasonable in the given situation.