(y+1)(y-8)=

Solution for (y+1)(y-8)= equation:

Simplifying
(y + 1)(y + -8) = 0

Reorder the terms:
(1 + y)(y + -8) = 0

Reorder the terms:
(1 + y)(-8 + y) = 0

Multiply (1 + y) * (-8 + y)
(1(-8 + y) + y(-8 + y)) = 0
((-8 * 1 + y * 1) + y(-8 + y)) = 0
((-8 + 1y) + y(-8 + y)) = 0
(-8 + 1y + (-8 * y + y * y)) = 0
(-8 + 1y + (-8y + y2)) = 0

Combine like terms: 1y + -8y = -7y
(-8 + -7y + y2) = 0

Solving
-8 + -7y + y2 = 0

Solving for variable 'y'.

Factor a trinomial.
(-1 + -1y)(8 + -1y) = 0

Subproblem 1
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
Subproblem 2
Set the factor '(8 + -1y)' equal to zero and attempt to solve:

Simplifying
8 + -1y = 0

Solving
8 + -1y = 0

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

Add '-8' to each side of the equation.
8 + -8 + -1y = 0 + -8

Combine like terms: 8 + -8 = 0
0 + -1y = 0 + -8
-1y = 0 + -8

Combine like terms: 0 + -8 = -8
-1y = -8

Divide each side by '-1'.
y = 8

Simplifying
y = 8
Solution
y = {-1, 8}