math
posted by lalith .
Ive got this equation system
{x+y= 0
{x^2 + y^2 = sqrt(125)
how do I solve it

I don't know why you have the { symbol in front of your two equations. I will ignore it.
The second equation is a circle about the origin with radius sqrt(125) = 11.18
The first equation can be rewritten y = x and is a line through the origin with slope 1 (second and fourth quadrants).
The two lines intersect at x= 11.18 sin 45 = 7.90, y = +7.905, and
x= 11.18 sin 45 = 7.90, y = 7.905