You are standing on the middle rung of a ladder. if you first climb up 3 rung then down 5 rung and then up 10 rung to get onto the top rung how many rung are on the ladder

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

Me because i don't understand how to do it.: )

The percent of change from 12 to 15