(5c-9)(5c+1)=

Solution for (5c-9)(5c+1)= equation:

Simplifying
(5c + -9)(5c + 1) = 0

Reorder the terms:
(-9 + 5c)(5c + 1) = 0

Reorder the terms:
(-9 + 5c)(1 + 5c) = 0

Multiply (-9 + 5c) * (1 + 5c)
(-9(1 + 5c) + 5c * (1 + 5c)) = 0
((1 * -9 + 5c * -9) + 5c * (1 + 5c)) = 0
((-9 + -45c) + 5c * (1 + 5c)) = 0
(-9 + -45c + (1 * 5c + 5c * 5c)) = 0
(-9 + -45c + (5c + 25c2)) = 0

Combine like terms: -45c + 5c = -40c
(-9 + -40c + 25c2) = 0

Solving
-9 + -40c + 25c2 = 0

Solving for variable 'c'.

Factor a trinomial.
(-1 + -5c)(9 + -5c) = 0

Subproblem 1
Set the factor '(-1 + -5c)' equal to zero and attempt to solve:

Simplifying
-1 + -5c = 0

Solving
-1 + -5c = 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 + -5c = 0 + 1

Combine like terms: -1 + 1 = 0
0 + -5c = 0 + 1
-5c = 0 + 1

Combine like terms: 0 + 1 = 1
-5c = 1

Divide each side by '-5'.
c = -0.2

Simplifying
c = -0.2
Subproblem 2
Set the factor '(9 + -5c)' equal to zero and attempt to solve:

Simplifying
9 + -5c = 0

Solving
9 + -5c = 0

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

Add '-9' to each side of the equation.
9 + -9 + -5c = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -5c = 0 + -9
-5c = 0 + -9

Combine like terms: 0 + -9 = -9
-5c = -9

Divide each side by '-5'.
c = 1.8

Simplifying
c = 1.8
Solution
c = {-0.2, 1.8}