This is a relatively complex problem and it took me a good 20 minutes to solve, I included a sketch I made myself while im solving this problem hope it helps with the explanation. (the dotted lines are my drawings, also I labeled the points just look at my graph)
Now to find <x, we can use the exterior angles theorem a couple of times.
<x=<p+<AGE
<x=30 degrees + <AGE
Now use the theorem again to find <AGE
<AGE=<q+<BIG
Now use substitution for <q and for <AGE
<x=30 degrees+60 degrees+ <BIG
We put this to the side for now and try solve for <CHD which is not very difficult
<CHD=180-45-20=115
We can also clearly figure out <HFI using vertical angles theorem.
<HFI=<Y
Because they all form a triangle we can conclude that <y+<BIG=180 degrees-<FHI= 180-115=65 degrees
substitution again
<x+<y=30+60+<BIG+<HFI (remember <HFI = <y vertical angles theorem)
<x+<y=30+60+65 (remember how we did before these 2 angles adds up to 65?)
<x+<y=155 degrees
Now please don't hate me on this, I'm sure there is more efficient ways to explain this problem, this is just my way from trial and error.
Tip for next time you are stuck on a geometry problem, don't be afraid to draw the graph again on paper and add lines to it!
You won't get everything perfect the first time you try but the more you practice the more comfortable you are with these problems, Hope my explanation helped!
**Just a note would you mind telling me where you got this problem form, its pretty challenging :)