Geometry have been absent and trying to catch up. any is appreciated : )

What value of x is in the solution set of 4x – 12 s 16 + 8x?

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

Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9