(x+11)²-x²=11
x²+22х+121-x²=11
22х+121=11
22х=-110
х=-110/22=-5
44+z²= (12+z)²
44+z²= 144+24z+z²
24z=44-144
24z=-100
z=-100/24=-25/6
69-(13-y)²=-y²
69-169+26y-y²=-y²
26y=100
y=100/26=50/13
31-t²=-(t-9)²
31-t²=-t²+18t-81
18t=31+81
18t=112
t=112/18=56/9