28a^2-192a-28=0

Solution for 28a^2-192a-28=0 equation:

Simplifying
28a2 + -192a + -28 = 0

Reorder the terms:
-28 + -192a + 28a2 = 0

Solving
-28 + -192a + 28a2 = 0

Solving for variable 'a'.

Factor out the Greatest Common Factor (GCF), '4'.
4(-7 + -48a + 7a2) = 0

Factor a trinomial.
4((-1 + -7a)(7 + -1a)) = 0

Ignore the factor 4.
Subproblem 1
Set the factor '(-1 + -7a)' equal to zero and attempt to solve:

Simplifying
-1 + -7a = 0

Solving
-1 + -7a = 0

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

Add '1' to each side of the equation.
-1 + 1 + -7a = 0 + 1

Combine like terms: -1 + 1 = 0
0 + -7a = 0 + 1
-7a = 0 + 1

Combine like terms: 0 + 1 = 1
-7a = 1

Divide each side by '-7'.
a = -0.1428571429

Simplifying
a = -0.1428571429
Subproblem 2
Set the factor '(7 + -1a)' equal to zero and attempt to solve:

Simplifying
7 + -1a = 0

Solving
7 + -1a = 0

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

Add '-7' to each side of the equation.
7 + -7 + -1a = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -1a = 0 + -7
-1a = 0 + -7

Combine like terms: 0 + -7 = -7
-1a = -7

Divide each side by '-1'.
a = 7

Simplifying
a = 7
Solution
a = {-0.1428571429, 7}