In the equation -y= 2x + 4, how do you remove the negative symbol from the y value in the equation?

Regardless of the variable, there is always an imaginary '1' in front of that variable. 

-y is the same as saying -1y
b is the same thing as saying ONE b 

That should make sense...

Lets divide each side by -1

-1y/-1 = 2x + 4/-1
y = -2x - 4

We have our equation now: y = -2x - 4