+619 Find all ordered pairs x, y of real numbers such that x+y=10 and x^2+y^2=64.
For example, to enter the solutions (2, 4) and (-3, 9), you would enter "(2,4),(-3,9)" (without the quotation marks).
+129657 x + y = 10 → y = 10 - x
x^2 + (10-x)^2 = 64
2x^2 - 20x + 100 = 64
2x^2 -20x + 36 = 0
x^2 -10x + 18 = 0
x^2 - 10x = -18
x^2 -10x + 25 = -18 + 25
(x - 5)^2 = 7 take both roots
x - 5 = sqrt 7 or x - 5 = -sqrt 7
x = 5 + sqrt 7 x = 5 - sqrt 7
(x , y) = (5 + sqrt 7 , 5 -sqrt 7 ) or ( 5 -sqrt 7 , 5 + sqrt 7)
