If x² - y² = 55, and x - y = 11, then y =
a. 8
b. 5
c. 3
d. -8
e. -3

If x-y = 11
then y = x-11
x²-(x-11)² =55
x²-(x²-22x+121) = 55
22x - 121 = 55
22x = 176
x =8
 y = x-11
y = 8-11
 y = -3. 
e is right option 
hope this helps