Решите уравнение: 31-t^2=-(t-9)^2

Question

Решите уравнение: 31-t^2=-(t-9)^2

Answer 1

31-t^2=-(t^2-18t+81)
31-t^2=-t^2+18t-81
31-t^2+t^2-18t+81=0
112=18t
t=112/18=56/9