Consider the sequence of steps to solve the equation: 3(x − 4) + 5x = 9x − 36 given ⇒ 3(x − 4) + 5x = 9x − 36 step 1 ⇒ 3x − 12 + 5x = 9x − 36 step 2 ⇒ 3x + 5x − 12 = 9x − 36 step 3 ⇒ 8x − 12 = 9x − 36 step 4 ⇒ 8x − 8x − 12 = 9x − 8x − 36 step 5 ⇒ 0 − 12 = x − 36 step 6 ⇒ −12 = x − 36 step 7 ⇒ −12 + 36 = x − 36 + 36 step 8 ⇒ 24 = x + 0 step 9 ⇒ 24 = x which property yields step 4? a) subtraction property of equality b) commutative property of addition c) addition property of equality d) additive inverse property