If you were to solve the following system by substitution, what would be the best variable to folve for and from what equation? 3x+6y=9 2x-10y=13 a) y in the first equation b) y in the second equation c) x in the second equation d) x in the first equation

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