問一條數學題

x+y=10
y=10-x ----3

Sub 3 into 2
x^2 + (10-x)^2 = 52
x^2 + 100 - 20x + x^2 = 52
2x^2 - 20x + 48 = 0
x^2 - 10x + 24 = 0
(x-6)(x-4) = 0
x=6 or x=4
y=4(when x=6) or 6(when x=4)

x+y=10----1
x^2+y^2=52----2
由1可得x=10-y----3
把3代2,得
(10-y)^2+y^2=52
100-20y+y^2+y^2-52=0
2y^2-20y+48=0
(y-6)(y-4)=0
y=6 或 y=4
將y=6代1,得
x+6=10
當y=6時,x=4
將y=4代1,得
x+4=10
當y=4時,x=6