Please help me... I will mark brainliest if you do ;)
An explanation would be appreciated as well!

Answer:
86
Step-by-step explanation:
The sum of the angles in a quadrilateral is 360 degrees
since EF is parallel to HG
m < E + m< H =180
y + 10 + 2y -31 =180
-21+ 3y= 180
3y = 180 + 21
3y = 201
y=67
m <E = 67 + 10 =77
m < F = 2*67 -40= 134 -40=94
m < H = 2*67-31 = 134 -31 = 103
m < G = 360 - (m<E+ m < F + m < H)
= 360 - ( 77+94+103)
= 360- 274
=86