-25=-y*y

Solution for -25=-y*y equation:

Simplifying
-25 = -1y * y

Multiply y * y
-25 = -1y2

Solving
-25 = -1y2

Solving for variable 'y'.

Move all terms containing y to the left, all other terms to the right.

Add 'y2' to each side of the equation.
-25 + y2 = -1y2 + y2

Combine like terms: -1y2 + y2 = 0
-25 + y2 = 0

Add '25' to each side of the equation.
-25 + 25 + y2 = 0 + 25

Combine like terms: -25 + 25 = 0
0 + y2 = 0 + 25
y2 = 0 + 25

Combine like terms: 0 + 25 = 25
y2 = 25

Simplifying
y2 = 25

Take the square root of each side:
y = {-5, 5}