Math
posted by Hollie on .
Hi,
I can't seem to figure out the answer to this problem.
Thanks to anyone who can help!
*Solve the system of equations. Write your solution(s) in the form (x,y).
y = x^2
x^2 + y^2 = 20

x^2+x^420=0
(x^24)(x^2+5)=0
(x+2)(x2)(x^2+5)=0
x= +2, x= +sqrt(5
(2,4)(2,4)(sqrt5,5)(sqrt5, 5) 
y + y^2 = 20
y^2 + y  20 = 0
(y4)(y+5) = 0
y = 4 or y = 5
y = 4 is easy, then x = 2 or +2
y = 5 means x = i sqrt 5
now go back and see which of those solutions work in the original
if y = 4 and x = 2 then
yes, y = x^2
and
yes, 4 + 16 = 20
if y = 4 and x = 2 then
yes, y = x^2
yes, 4 + 16 = 20
if y = 5 and x = i sqrt 5
yes, y = x^2
yes, 5 + 25 = 20 
I left out y = 5, x = i sqrt 5
y = (isqrt5)^2 = 5 yes
5 + 25 = 20 yes