1. Set Y to 0, solve for x. Then X can be any number greater than the answer.
y = -1.5x +7.5
0 = -1.5x +7.5
Subtract 7.5 from both sides:
-7.5 = -1.5x
Divide both sides by -1.5
X = -7.5 / -1.5x = 5
X > 5
2. The equation is the same as the first one, but now they want Y to be less than 0, so the answer would be the reverse of the first answer:
X < 5
