In the figure, line m is parallel to line n.
1) Find m
2) Name the postulates and/or theorems you used in finding your answer to Part 1. Explain each postulate or theorem.
+128408 I think we want to find x, not m
Angle CDG = Angle JDE { vertical angles}
Angle JDE = Angle HCD {corresponding angles }
Thus
Angle CDG = Angle HCD { substitution }
So
5x - 5 = 3x + 13 add 5 to both sides, subtract 3x from both sides
2x = 18 divide both sides by 2
x = 9
+9466 Notice that ∠BCH and ∠HCD form a straight line, so they must add to 180° .
∠BCH + ∠HCD = 180°
And...
m∠HCD = (3x + 13)° CPhill already found that x = 9 , so that means
m∠HCD = (3(9) + 13)°
m∠HCD = (27 + 13)°
m∠HCD = 40°
So.....remember...
∠BCH + ∠HCD = 180°
∠BCH + 40° = 180°
Can you finish it from here? 
