Answer :
x^2 + y^2 = 25 ...... Equation (1)
2x + y = 10
y = 10 - 2x ........ Equation (2)
Substituting equation (2) in equation (1), we get,
x^2 + ( 10 - 2x )^2 = 25
x^2 + 100 - 40x + 4x^2 = 25
5x^2 - 40x +100 - 25 = 0
5x^2 - 40x + 75 = 0
5 ( x^2 - 8x + 15 ) = 0
x^2 - 8x + 15 = 0
x^2 - 5x - 3x + 15 = 0
x ( x - 5 ) -3 ( x - 5 ) = 0
( x -5 ) ( x - 3 ) = 0
Therefore, x = 5 and x = 3
If x = 5 then, y = 10 - 2(5)
y = 10 - 10
y = 0
If x = 3 then, y = 10 - 2(3)
y = 10 - 6
y = 4
Therefore, solution set = { 5 , 0 } and { 3 , 4 }