(y+9)(y-1)=0

Solution for (y+9)(y-1)=0 equation:

Simplifying
(y + 9)(y + -1) = 0

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

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

Multiply (9 + y) * (-1 + y)
(9(-1 + y) + y(-1 + y)) = 0
((-1 * 9 + y * 9) + y(-1 + y)) = 0
((-9 + 9y) + y(-1 + y)) = 0
(-9 + 9y + (-1 * y + y * y)) = 0
(-9 + 9y + (-1y + y2)) = 0

Combine like terms: 9y + -1y = 8y
(-9 + 8y + y2) = 0

Solving
-9 + 8y + y2 = 0

Solving for variable 'y'.

Factor a trinomial.
(-9 + -1y)(1 + -1y) = 0

Subproblem 1
Set the factor '(-9 + -1y)' equal to zero and attempt to solve:

Simplifying
-9 + -1y = 0

Solving
-9 + -1y = 0

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

Add '9' to each side of the equation.
-9 + 9 + -1y = 0 + 9

Combine like terms: -9 + 9 = 0
0 + -1y = 0 + 9
-1y = 0 + 9

Combine like terms: 0 + 9 = 9
-1y = 9

Divide each side by '-1'.
y = -9

Simplifying
y = -9
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 = {-9, 1}