-7d^2+2d+9=0

Solution for -7d^2+2d+9=0 equation:

Simplifying
-7d2 + 2d + 9 = 0

Reorder the terms:
9 + 2d + -7d2 = 0

Solving
9 + 2d + -7d2 = 0

Solving for variable 'd'.

Factor a trinomial.
(9 + -7d)(1 + d) = 0

Subproblem 1
Set the factor '(9 + -7d)' equal to zero and attempt to solve:

Simplifying
9 + -7d = 0

Solving
9 + -7d = 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 + -7d = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -7d = 0 + -9
-7d = 0 + -9

Combine like terms: 0 + -9 = -9
-7d = -9

Divide each side by '-7'.
d = 1.285714286

Simplifying
d = 1.285714286
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 = {1.285714286, -1}