Question

Find the measure of angle CDE.

Answer 1

http://roads.advancedacademics.com/contentserver/content/roadssection/279432/questions/assessments/t-introductiontrianglesquiz/geometry_unit_4_1_quiz_v3_14q.gif

Answer 2

Call angle EDF y. so y+x+50=180
y=180-50-x
y =130-x

Using angle CDE and the supplement y, (2x-15)+y=180
Substitute (130-x) for y
(2x-15)+(130-x)=180

Solve for x and then plug back into (2x-15)