9c^2-8c-1=0

Solution for 9c^2-8c-1=0 equation:

Simplifying
9c2 + -8c + -1 = 0

Reorder the terms:
-1 + -8c + 9c2 = 0

Solving
-1 + -8c + 9c2 = 0

Solving for variable 'c'.

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

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

Simplifying
-1 + -9c = 0

Solving
-1 + -9c = 0

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

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

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

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

Divide each side by '-9'.
c = -0.1111111111

Simplifying
c = -0.1111111111
Subproblem 2
Set the factor '(1 + -1c)' equal to zero and attempt to solve:

Simplifying
1 + -1c = 0

Solving
1 + -1c = 0

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

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

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

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

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

Simplifying
c = 1
Solution
c = {-0.1111111111, 1}