Please help me lol I need to write 20 characters so yea help

Simonne used the following steps to simplify the given expression. 12 - 3(-2x + 4) step 1: 12 + (–3)·(–2x) + (–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? a. identity property of addition b. inverse property of addition c. associative property of addition d. commutative property of addition

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15