1)(x+11-x)(x+11+x)=11
11(2x+11)=11
2x= -10
x= -5
2)44+z^2-144-24z-z^2=0
-100-24z=0
z= -25/6
3)69-169+26y-y^2+y^2=0
-100+26y=0
y=50/13
4)31-t^2=-t^2+18t-81
31-t^2+t^2-18t+81=0
112=18t
t=56/9
5a-(a+1)(4a+1)=5a-(4a²+a+4a+1)=5a-4a²-a-4a-1=5a-4a²-5a-1=-4a²-1