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.
(-1 + -1d)(9 + -7d) = 0

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

Simplifying
-1 + -1d = 0

Solving
-1 + -1d = 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 + -1d = 0 + 1

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

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

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

Simplifying
d = -1
Subproblem 2
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
Solution
d = {-1, 1.285714286}