d^2+22d+21=0

Solution for d^2+22d+21=0 equation:

Simplifying
d2 + 22d + 21 = 0

Reorder the terms:
21 + 22d + d2 = 0

Solving
21 + 22d + d2 = 0

Solving for variable 'd'.

Factor a trinomial.
(21 + d)(1 + d) = 0

Subproblem 1
Set the factor '(21 + d)' equal to zero and attempt to solve:

Simplifying
21 + d = 0

Solving
21 + d = 0

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

Add '-21' to each side of the equation.
21 + -21 + d = 0 + -21

Combine like terms: 21 + -21 = 0
0 + d = 0 + -21
d = 0 + -21

Combine like terms: 0 + -21 = -21
d = -21

Simplifying
d = -21
Subproblem 2
Set the factor '(1 + d)' equal to zero and attempt to solve:

Simplifying
1 + d = 0

Solving
1 + d = 0

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

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

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

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

Simplifying
d = -1
Solution
d = {-21, -1}