In Exercises 5-14, solve the equation. Justify each step.
Check your solution. (See Example 1.)
5. x+5=8
6. m + 9 = 2
7. y - 4 = 3
8. s-2=1
9. w+ 3 = - 4
10. n-6= - 7
11. - 14 = p - 11
12. 0 = 4 + 9
13. r +(-8) = 10
14. t-(-5) = 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