Choose the property that justifies each statement.
If -3x = 15, then x = -5. __________
If x = 9, then 9 = x. __________
If x = -3, then x^{2}+5x-9 = (-3)^{2}+5(-3)-9. __________
If x + 8 = 24, then x = 16. __________
-5(2x-3) = -10x+15 __________
If \frac{3x}{5} = 21, then 3x = 105. __________
If h = 18, then 17 - 4h = 17 - 4(18). __________
If 7x + 2 = 16, then 16 = 7x + 2. __________
If 17x + 5 = 39, then 17x = 34. __________