Take an equation:

-a^2+2

It's easy enough to start solving for a:

-a^2=-2

Now I am aware that taking the square root at this point would mean I would have to start using an imaginary number "i" as it is called. It is my understanding right now that:

a^2=2

is an equivalent equation to -a^2=-2 since both sides of the equation could be divided by negative one?

I've been reviewing my algebra and so when a square root of both sides of an equation takes place I have to use a +- (plus-minus) sign?

Is that really true in all cases?

Thanks in advance...