Y^2=4 Y=?

Y^{2} = 4 Take the ± square root of both sides.

Y = ±√4

Y = ± 2

y^{2} = 4

y=2

because you can take the square root from y^{2} which gives you y and then take the square root of 4 which is equivalent to 2.

Sorry guest but Hectictar is correct :)

By convention

\(\sqrt{y^2}=+y\)

that is true

BUT this is different becasuse the square root sign is not in the question. So

If

\(y^2=4\\ then\\ y=\pm\sqrt4=\pm2\)