(t+9)(t-12)=0

Solution for (t+9)(t-12)=0 equation:

Simplifying
(t + 9)(t + -12) = 0

Reorder the terms:
(9 + t)(t + -12) = 0

Reorder the terms:
(9 + t)(-12 + t) = 0

Multiply (9 + t) * (-12 + t)
(9(-12 + t) + t(-12 + t)) = 0
((-12 * 9 + t * 9) + t(-12 + t)) = 0
((-108 + 9t) + t(-12 + t)) = 0
(-108 + 9t + (-12 * t + t * t)) = 0
(-108 + 9t + (-12t + t2)) = 0

Combine like terms: 9t + -12t = -3t
(-108 + -3t + t2) = 0

Solving
-108 + -3t + t2 = 0

Solving for variable 't'.

Factor a trinomial.
(-9 + -1t)(12 + -1t) = 0

Subproblem 1
Set the factor '(-9 + -1t)' equal to zero and attempt to solve:

Simplifying
-9 + -1t = 0

Solving
-9 + -1t = 0

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

Add '9' to each side of the equation.
-9 + 9 + -1t = 0 + 9

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

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

Divide each side by '-1'.
t = -9

Simplifying
t = -9
Subproblem 2
Set the factor '(12 + -1t)' equal to zero and attempt to solve:

Simplifying
12 + -1t = 0

Solving
12 + -1t = 0

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

Add '-12' to each side of the equation.
12 + -12 + -1t = 0 + -12

Combine like terms: 12 + -12 = 0
0 + -1t = 0 + -12
-1t = 0 + -12

Combine like terms: 0 + -12 = -12
-1t = -12

Divide each side by '-1'.
t = 12

Simplifying
t = 12
Solution
t = {-9, 12}