Well straight up I can tell you the answer is 65 for CDE, I used simultaneous equations to find this
You know that the addition of all angles is 180, so then you know that the remaining interior angles must equal to 130 because 180 take the already known angle, 50, is 130, so that means that your first equation is going to be
\[x+y=130\]
Your second equation is going to be 180, because that is the angle of the straight line take away the equation in CDE equals y
\[180-(2x-15)=y\]
You can now view it as;
\[x+y = 130, 2 x+y = 195\]
\[x=130-y, 2(130-y)+y=195\]
\[260-2y+y=195\]
\[65-y=o\]
\[y=65\]
\[x+(65)=130\]
\[x=130-65\]
\[x=65\]