(d-3)*(d+9)=

Solution for (d-3)*(d+9)= equation:

Simplifying
(d + -3)(d + 9) = 0

Reorder the terms:
(-3 + d)(d + 9) = 0

Reorder the terms:
(-3 + d)(9 + d) = 0

Multiply (-3 + d) * (9 + d)
(-3(9 + d) + d(9 + d)) = 0
((9 * -3 + d * -3) + d(9 + d)) = 0
((-27 + -3d) + d(9 + d)) = 0
(-27 + -3d + (9 * d + d * d)) = 0
(-27 + -3d + (9d + d2)) = 0

Combine like terms: -3d + 9d = 6d
(-27 + 6d + d2) = 0

Solving
-27 + 6d + d2 = 0

Solving for variable 'd'.

Factor a trinomial.
(-9 + -1d)(3 + -1d) = 0

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

Simplifying
-9 + -1d = 0

Solving
-9 + -1d = 0

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

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

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

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

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

Simplifying
d = -9
Subproblem 2
Set the factor '(3 + -1d)' equal to zero and attempt to solve:

Simplifying
3 + -1d = 0

Solving
3 + -1d = 0

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

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

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

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

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

Simplifying
d = 3
Solution
d = {-9, 3}