So hmm check the picture below
what's the width? well, w = l + 3

The given angles forms linear pair, and we know the angles forming linear pair are supplementary,
Therefore,
Angle MHJ + Angle MHL = 180°
Let's solve :
Value of variable m = 10°

Simply present that you would split them up as a factor of two. ( make two lines going either vertically or horizontally. place in varriations, a marble in one line and a marble in the other and then count the leftover
Y = -15 is the answer and blah