Okay, here are the steps to solve this problem:
1) Since ACDE is isosceles with base EC, the angles at the base (mECD and mCEA) are equal. Let's call this common angle measure θ.
2) We know: mZD = (2x + 42)°
So, (2x + 42) + θ = 180° (angles sum to 180° in a triangle)
2x + 42 + θ = 180
=> 2x = 138
=> x = 69
3) Substitute x = 69 into mZE = (4x + 14)°
=> mZE = (4(69) + 14) = 278°
4) Now we have all 3 angles:
mECD = mCEA = θ (these are equal, common base angle)
mZD = (2)(69) + 42 = 174°
mZE = 278°
5) As a check:
174 + 278 + θ = 180
θ = 128
So the degree measures of the angles are:
mECD = mCEA = 128° (common base angle)
mZD = 174°
mZE = 278°
Let me know if you have any other questions! I'm happy to explain further.