-10=(5y-2)(5y-2)

Solution for -10=(5y-2)(5y-2) equation:

Simplifying
-10 = (5y + -2)(5y + -2)

Reorder the terms:
-10 = (-2 + 5y)(5y + -2)

Reorder the terms:
-10 = (-2 + 5y)(-2 + 5y)

Multiply (-2 + 5y) * (-2 + 5y)
-10 = (-2(-2 + 5y) + 5y * (-2 + 5y))
-10 = ((-2 * -2 + 5y * -2) + 5y * (-2 + 5y))
-10 = ((4 + -10y) + 5y * (-2 + 5y))
-10 = (4 + -10y + (-2 * 5y + 5y * 5y))
-10 = (4 + -10y + (-10y + 25y2))

Combine like terms: -10y + -10y = -20y
-10 = (4 + -20y + 25y2)

Solving
-10 = 4 + -20y + 25y2

Solving for variable 'y'.

Combine like terms: -10 + -4 = -14
-14 + 20y + -25y2 = 4 + -20y + 25y2 + -4 + 20y + -25y2

Reorder the terms:
-14 + 20y + -25y2 = 4 + -4 + -20y + 20y + 25y2 + -25y2

Combine like terms: 4 + -4 = 0
-14 + 20y + -25y2 = 0 + -20y + 20y + 25y2 + -25y2
-14 + 20y + -25y2 = -20y + 20y + 25y2 + -25y2

Combine like terms: -20y + 20y = 0
-14 + 20y + -25y2 = 0 + 25y2 + -25y2
-14 + 20y + -25y2 = 25y2 + -25y2

Combine like terms: 25y2 + -25y2 = 0
-14 + 20y + -25y2 = 0

Begin completing the square.  Divide all terms by
-25 the coefficient of the squared term: 

Divide each side by '-25'.
0.56 + -0.8y + y2 = 0

Move the constant term to the right:

Add '-0.56' to each side of the equation.
0.56 + -0.8y + -0.56 + y2 = 0 + -0.56

Reorder the terms:
0.56 + -0.56 + -0.8y + y2 = 0 + -0.56

Combine like terms: 0.56 + -0.56 = 0.00
0.00 + -0.8y + y2 = 0 + -0.56
-0.8y + y2 = 0 + -0.56

Combine like terms: 0 + -0.56 = -0.56
-0.8y + y2 = -0.56

The y term is -0.8y.  Take half its coefficient (-0.4).
Square it (0.16) and add it to both sides.

Add '0.16' to each side of the equation.
-0.8y + 0.16 + y2 = -0.56 + 0.16

Reorder the terms:
0.16 + -0.8y + y2 = -0.56 + 0.16

Combine like terms: -0.56 + 0.16 = -0.4
0.16 + -0.8y + y2 = -0.4

Factor a perfect square on the left side:
(y + -0.4)(y + -0.4) = -0.4

Can't calculate square root of the right side.

The solution to this equation could not be determined.