How many solutions does the following system of equations have x = −2 and x2 + y2 = 4

Question

How many solutions does the following system of equations have x = −2   and  x2 + y2 = 4

anonymous · Answer

y^2 + 4 = 4
y^2 = 0

y=0

If y was a number other than zero, then it would be +/- that number (two solutions

anonymous · Answer

So say y^2 = 9, then y =3 and y=-3

.sam. · Answer

x2 + y2 = 4
when x=-2,
$$(-2)^2 + y^2=4$$
$$4+y^2=4$$
$$y^2=2$$
$$y=\pm \sqrt{2}$$
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when 
$$y=+\sqrt{2}$$
$$x^2 +2=4$$
$$x^2 =2$$
$$x=\pm \sqrt{2}$$
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when$$ y=-\sqrt{2}$$
$$x=\pm \sqrt{2}$$
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4 solutions

anonymous · Answer

@.Sam. maybe I'm wrong, but:

(-2)^2+y^2 = 4

4 + y^2 = 4

-4 + 4 + y^2 = 4 -4

y^2 = 0  does not = 2