1. -18 +15x = 3(4x-6) + 3x
-18 + 15x = 12x - 18 + 3x
-18 + 3x = -18 + 3x
3x = 3x
x = All Real Numbers (because we don't know what x is since the equation is 3x = 3x, we can assume that it is all "real" numbers)
2. -10 + 5x = 5(x - 3) + 5
-10 + 5x = 5x - 15 + 5
-10 = -10
Answer Undefined (because the x coefficients canceled out, we don't know what x even is, so we can claim it as undefined.)
