Answer:
ZY = 23
Step-by-step explanation:
Given in the picture:
ZY = 7a + 2
ZD = DX, diagonals of parallelograms bisect each-other so
3(2a+1) = 9a -6 , given in the picture
6a +3 = 9a - 6, subtract 9a and 3 from both sides
6a -9a = -6 -3, combine like terms
-3a = -9, divide both sides by -3
a = 3
ZY = 7a + 2
ZY = 7·3 + 2
ZY = 23
