Amber simplified the expression (a4+7a−16)−(12a3−5a+3) below. Amber made her first error at, Problem: (a4+7a−16)−(12a3−5a+3)

Step 1: a4+7a−16−12a3+5a−3

Step 2: a4−12a3+7a+5a−16−3

Step 3: −11a+7a+5a−16−3

Step 4: −11a+12a−16−3

Step 5: −11a+12a−19

What is the next step in the given proof? choose the most logical approach. a. statement: m 1 + m 2 + 2(m 3) = 180° reason: angle addition b. statement: m 1 + m 3 = m 2 + m 3 reason: transitive property of equality c. statement: m 1 = m 2 reason: subtraction property of equality d. statement: m 1 + m 2 = m 2 + m 3 reason: substitution property of equality e. statement: 2(m 1) = m 2 + m 3 reason: substitution property of equality