Achueca has 20 plates if theres 30 people how much does she need more

Can someone me and plz do the problem

Question: a) does the given set of points represent a linear function? how do you know? b) assume that the point (-2,4) lies on the graph of a line. what y-values could complete this set of ordered pairs that lie on the same line: (- (hint: there are several correct answ

3x + 4y = 5 x- 3y = -7 solve by substitution