Find the value of a in the parallelogram. An unlabeled parallelogram has one angle labeled parenthesis 6 a minus 4 right parenthesis degrees and the opposite angle labeled left parenthesis 2 a plus 68 right parenthesis degrees.

(1 point)

a=18

a=16

a=14.5

a=9

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