2.4 Algebraic Proofs

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.

12.5 = 12.5

-9.01 = -9.01

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.

5x = 5x

If 17x + 5 = 39, then 17x = 34.