d^2+8d+7=0

Solution for d^2+8d+7=0 equation:

Simplifying
d2 + 8d + 7 = 0

Reorder the terms:
7 + 8d + d2 = 0

Solving
7 + 8d + d2 = 0

Solving for variable 'd'.

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

Subproblem 1
Set the factor '(7 + d)' equal to zero and attempt to solve:

Simplifying
7 + d = 0

Solving
7 + d = 0

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

Add '-7' to each side of the equation.
7 + -7 + d = 0 + -7

Combine like terms: 7 + -7 = 0
0 + d = 0 + -7
d = 0 + -7

Combine like terms: 0 + -7 = -7
d = -7

Simplifying
d = -7
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 = {-7, -1}