Given: 1 and 2 are supplementary angles Prove: l || m STATEMENT REASON
1.∠1 and ∠2 are supplementary angles 1. Given
2. m∠1 + m∠2 = 180° 2.
3. ∠1 and ∠3 are supplementary angles 3. Exterior sides in opposite rays
4. 4.
5. m∠1 + m∠2 = m∠1 + m∠3 5.
6. 6.
7. l || m 7.

Simonne used the following steps to simplify the given expression. 12-3(-2x+4) step 1: 12+(-)+(-3)(4) step 2: 12+6x+(-12) step 3: 12+(-12)+6x step 4: 0+6x step 5: 6x what property of real numbers was used to transition from step 3 to step 4? •identity property of addition •inverse property of addition •associative property of addition •commutative property of addition