Question 931199
x + y = 9   0r y = {{{9-x}}}
....
(9-x)^2 + x^2 = 261
81 - 18x + x^2 + x^2 = 261
2x^2 - 18x  - 180 = 0
x^2 - 9x - 90 = 0
(x+6)(x-15)= 0
x = 15  and y = -6
0r
x = -6  and y = 15
(15,-6)  and (-6,15) solutions for this System
And..checking
225 + 36 = 261