Help plsss it’s (Graphing Lines in Slope-Intercept Form) 7th grade work

Do u just plot the numbers on the graph like (1,

As a self-employed seamstress, you know that it takes 7 yards of material to make 3 jackets. you bought 15 yards of material to make 7 jackets. did you buy enough material? if not, how much were you over or under?

Betty correctly answers 30 questions on your math test there are 40 questions on the test what percent of the questions did she answered incorrectly