-4(y-1)(-y-3)=0

Solution for -4(y-1)(-y-3)=0 equation:

Simplifying
-4(y + -1)(-1y + -3) = 0

Reorder the terms:
-4(-1 + y)(-1y + -3) = 0

Reorder the terms:
-4(-1 + y)(-3 + -1y) = 0

Multiply (-1 + y) * (-3 + -1y)
-4(-1(-3 + -1y) + y(-3 + -1y)) = 0
-4((-3 * -1 + -1y * -1) + y(-3 + -1y)) = 0
-4((3 + 1y) + y(-3 + -1y)) = 0
-4(3 + 1y + (-3 * y + -1y * y)) = 0
-4(3 + 1y + (-3y + -1y2)) = 0

Combine like terms: 1y + -3y = -2y
-4(3 + -2y + -1y2) = 0
(3 * -4 + -2y * -4 + -1y2 * -4) = 0
(-12 + 8y + 4y2) = 0

Solving
-12 + 8y + 4y2 = 0

Solving for variable 'y'.

Factor out the Greatest Common Factor (GCF), '4'.
4(-3 + 2y + y2) = 0

Factor a trinomial.
4((-3 + -1y)(1 + -1y)) = 0

Ignore the factor 4.
Subproblem 1
Set the factor '(-3 + -1y)' equal to zero and attempt to solve:

Simplifying
-3 + -1y = 0

Solving
-3 + -1y = 0

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

Add '3' to each side of the equation.
-3 + 3 + -1y = 0 + 3

Combine like terms: -3 + 3 = 0
0 + -1y = 0 + 3
-1y = 0 + 3

Combine like terms: 0 + 3 = 3
-1y = 3

Divide each side by '-1'.
y = -3

Simplifying
y = -3
Subproblem 2
Set the factor '(1 + -1y)' equal to zero and attempt to solve:

Simplifying
1 + -1y = 0

Solving
1 + -1y = 0

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

Add '-1' to each side of the equation.
1 + -1 + -1y = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -1y = 0 + -1
-1y = 0 + -1

Combine like terms: 0 + -1 = -1
-1y = -1

Divide each side by '-1'.
y = 1

Simplifying
y = 1
Solution
y = {-3, 1}