To find the solution for KMC use the following geometry theorems:
Vertical angles are congruent so their measures are equal.
Supplementary angles form a straight line have when added together equal 180.
HMC and RMK are vertical angles because they are across a vertex from each other. They are congruent and have equal measures. So M can be solved for by:
5m+15=7m+1
5m+15-1=7m+1-1
5m+14=7m
5m-5m+15=7m-5m
15=2m
7.5=m
Now substitute m=7.5 into one of the angles, either HMC or RMK.
7(7.5)+1 = 52.5+1 = 53.5
Notice, RMK and KMC are supplementary because they form a straight line together. This means 53.5 + KMC = 180.
Since you are writing this in slope-intercept equation you will want to isolate the y. Therefore move the -8x over making it into -2y=8x+10. Then simply divide by the -2. And your equation will be y=-4x-5.
