Y2 = 4 Take the ± square root of both sides.
Y = ±√4
Y = ± 2
y2 = 4
because you can take the square root from y2 which gives you y and then take the square root of 4 which is equivalent to 2.
Sorry guest but Hectictar is correct :)
that is true
BUT this is different becasuse the square root sign is not in the question. So
\(y^2=4\\ then\\ y=\pm\sqrt4=\pm2\)