So since these angles are across from each other they have to equal each other so:
11(y-10)=4y-5
11y-110=4y-5
-4y -4y
7y-110=-5
+110 +110
7y=105
divide by seven on both sides of the equation
y=15
So you would plug 15 into the equation :11(15-10) and with Order or Operations you would do parenthesis first which is 5 times 11 which equals 55 and that would be the measure of your angle