(7c^2-3c+6)-(-9c^2+2c-8)=

Solution for (7c^2-3c+6)-(-9c^2+2c-8)= equation:

Simplifying
(7c2 + -3c + 6) + -1(-9c2 + 2c + -8) = 0

Reorder the terms:
(6 + -3c + 7c2) + -1(-9c2 + 2c + -8) = 0

Remove parenthesis around (6 + -3c + 7c2)
6 + -3c + 7c2 + -1(-9c2 + 2c + -8) = 0

Reorder the terms:
6 + -3c + 7c2 + -1(-8 + 2c + -9c2) = 0
6 + -3c + 7c2 + (-8 * -1 + 2c * -1 + -9c2 * -1) = 0
6 + -3c + 7c2 + (8 + -2c + 9c2) = 0

Reorder the terms:
6 + 8 + -3c + -2c + 7c2 + 9c2 = 0

Combine like terms: 6 + 8 = 14
14 + -3c + -2c + 7c2 + 9c2 = 0

Combine like terms: -3c + -2c = -5c
14 + -5c + 7c2 + 9c2 = 0

Combine like terms: 7c2 + 9c2 = 16c2
14 + -5c + 16c2 = 0

Solving
14 + -5c + 16c2 = 0

Solving for variable 'c'.

Begin completing the square.  Divide all terms by
16 the coefficient of the squared term: 

Divide each side by '16'.
0.875 + -0.3125c + c2 = 0

Move the constant term to the right:

Add '-0.875' to each side of the equation.
0.875 + -0.3125c + -0.875 + c2 = 0 + -0.875

Reorder the terms:
0.875 + -0.875 + -0.3125c + c2 = 0 + -0.875

Combine like terms: 0.875 + -0.875 = 0.000
0.000 + -0.3125c + c2 = 0 + -0.875
-0.3125c + c2 = 0 + -0.875

Combine like terms: 0 + -0.875 = -0.875
-0.3125c + c2 = -0.875

The c term is -0.3125c.  Take half its coefficient (-0.15625).
Square it (0.0244140625) and add it to both sides.

Add '0.0244140625' to each side of the equation.
-0.3125c + 0.0244140625 + c2 = -0.875 + 0.0244140625

Reorder the terms:
0.0244140625 + -0.3125c + c2 = -0.875 + 0.0244140625

Combine like terms: -0.875 + 0.0244140625 = -0.8505859375
0.0244140625 + -0.3125c + c2 = -0.8505859375

Factor a perfect square on the left side:
(c + -0.15625)(c + -0.15625) = -0.8505859375

Can't calculate square root of the right side.

The solution to this equation could not be determined.