1) -х2+(х+11)2=11
121+х2+22х-х2=11
110+22х=0
х=-110:22
х=-5
Отв: -5
2) 69-(13-у)² = -у²
69 - 169+26у - у² + у² = 0
26у = 100
у= 100/26 = 50/13
Отв: 50/13
3) 44+z²=(12+z)²
-z²-44 + 144 + 24z + z² = 0
24z = -100
z = -100/24 = - 25/6
Отв: - 25/6
4) 31-t²=-(t-9)²
t²-31-t²+18t-81 = 0
18t = 112
t = 112/18 = 56/9
Отв: 56/9