Use an inequality:
S = sum
7 + 7 < S < 8 + 9
14 < S < 17
so the sum is between 14 and 17
No, for thing 2x and 3x have different slopes. moreover they have different y and x intercepts. you can set them equal to find an intersection since they don't have the same slope but yea
The first one 7x+15.50=100
