Please help me with the math below

Use the elimination method to find the solution to the system of equations. 2x - 3y = -9 -x + 3y = 6

There is diarrhea on the floor. what do i do? my mum gonna see that i diarrhea on the floor! * don't report, i'm serious! *

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