Solve the simultaneous equations... help please??!!?

x+y = 2
y=2-x

x^2+y^2=9
x^2 + (2-x)^2 = 9
x^2 + (4 -4x+x^2) = 9
2x^2 - 4x + 4 = 9
2x^2-4x-5 = 0

This equation is of form ax^2+bx+c=0
a = 2 b = -4 c = -5
x=[-b+/-sqrt(b^2-4ac)]/2a]
x=[4 +/-sqrt(-4^2-4(2)(-5)]/(2)(2)
discriminant is b^2-4ac =56
x=[4 +√(56)] / (2)(2)
x = (1 + √56 /4)
x=[4 -√(56)] / (2)(2)
x = (1 - √56 /4)

x = (1 + √56 /4)
y= 2 - x
y = 2 - (1 + √56 /4) = 1 - √56 /4

(x,y) = ( (1 + √56 /4) , (1 - √56 /4) ) ----------- (1)

x = (1 - √56 /4)
y= 2 - (1 - √56 /4) = 1 + √56 /4

(x,y) = ( (1 - √56 /4) , (1 + √56 /4) ) ----------- (2)

(1) and (2) are solutions

x^2 + (2-x)^2 = 9 =>
2x^2 - 4x - 5 = 0 =>
x = 1 +/- (1/4)*sqrt(16+40)
= 1 +/- (1/2)*sqrt(14);
and y = 1 -/+ (1/2)*sqrt(14).

The solution pairs will have an x and y with opposite signs on the radical term.