(5x^2-7x-6)+(8x^2+6x-1)=

Solution for (5x^2-7x-6)+(8x^2+6x-1)= equation:

Simplifying
(5x2 + -7x + -6) + (8x2 + 6x + -1) = 0

Reorder the terms:
(-6 + -7x + 5x2) + (8x2 + 6x + -1) = 0

Remove parenthesis around (-6 + -7x + 5x2)
-6 + -7x + 5x2 + (8x2 + 6x + -1) = 0

Reorder the terms:
-6 + -7x + 5x2 + (-1 + 6x + 8x2) = 0

Remove parenthesis around (-1 + 6x + 8x2)
-6 + -7x + 5x2 + -1 + 6x + 8x2 = 0

Reorder the terms:
-6 + -1 + -7x + 6x + 5x2 + 8x2 = 0

Combine like terms: -6 + -1 = -7
-7 + -7x + 6x + 5x2 + 8x2 = 0

Combine like terms: -7x + 6x = -1x
-7 + -1x + 5x2 + 8x2 = 0

Combine like terms: 5x2 + 8x2 = 13x2
-7 + -1x + 13x2 = 0

Solving
-7 + -1x + 13x2 = 0

Solving for variable 'x'.

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

Divide each side by '13'.
-0.5384615385 + -0.07692307692x + x2 = 0

Move the constant term to the right:

Add '0.5384615385' to each side of the equation.
-0.5384615385 + -0.07692307692x + 0.5384615385 + x2 = 0 + 0.5384615385

Reorder the terms:
-0.5384615385 + 0.5384615385 + -0.07692307692x + x2 = 0 + 0.5384615385

Combine like terms: -0.5384615385 + 0.5384615385 = 0.0000000000
0.0000000000 + -0.07692307692x + x2 = 0 + 0.5384615385
-0.07692307692x + x2 = 0 + 0.5384615385

Combine like terms: 0 + 0.5384615385 = 0.5384615385
-0.07692307692x + x2 = 0.5384615385

The x term is -0.07692307692x.  Take half its coefficient (-0.03846153846).
Square it (0.001479289941) and add it to both sides.

Add '0.001479289941' to each side of the equation.
-0.07692307692x + 0.001479289941 + x2 = 0.5384615385 + 0.001479289941

Reorder the terms:
0.001479289941 + -0.07692307692x + x2 = 0.5384615385 + 0.001479289941

Combine like terms: 0.5384615385 + 0.001479289941 = 0.539940828441
0.001479289941 + -0.07692307692x + x2 = 0.539940828441

Factor a perfect square on the left side:
(x + -0.03846153846)(x + -0.03846153846) = 0.539940828441

Calculate the square root of the right side: 0.734806661

Break this problem into two subproblems by setting 
(x + -0.03846153846) equal to 0.734806661 and -0.734806661.

Subproblem 1
x + -0.03846153846 = 0.734806661

Simplifying
x + -0.03846153846 = 0.734806661

Reorder the terms:
-0.03846153846 + x = 0.734806661

Solving
-0.03846153846 + x = 0.734806661

Solving for variable 'x'.

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

Add '0.03846153846' to each side of the equation.
-0.03846153846 + 0.03846153846 + x = 0.734806661 + 0.03846153846

Combine like terms: -0.03846153846 + 0.03846153846 = 0.00000000000
0.00000000000 + x = 0.734806661 + 0.03846153846
x = 0.734806661 + 0.03846153846

Combine like terms: 0.734806661 + 0.03846153846 = 0.77326819946
x = 0.77326819946

Simplifying
x = 0.77326819946

Subproblem 2
x + -0.03846153846 = -0.734806661

Simplifying
x + -0.03846153846 = -0.734806661

Reorder the terms:
-0.03846153846 + x = -0.734806661

Solving
-0.03846153846 + x = -0.734806661

Solving for variable 'x'.

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

Add '0.03846153846' to each side of the equation.
-0.03846153846 + 0.03846153846 + x = -0.734806661 + 0.03846153846

Combine like terms: -0.03846153846 + 0.03846153846 = 0.00000000000
0.00000000000 + x = -0.734806661 + 0.03846153846
x = -0.734806661 + 0.03846153846

Combine like terms: -0.734806661 + 0.03846153846 = -0.69634512254
x = -0.69634512254

Simplifying
x = -0.69634512254

Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {0.77326819946, -0.69634512254}