x2-(-3x)+4+7x2-8x-6=0

Solution for x2-(-3x)+4+7x2-8x-6=0 equation:

x2-(-3x)+4+7x^2-8x-6=0

We add all the numbers together, and all the variables

8x^2-8x-(-3x)-2=0

We get rid of parentheses

8x^2-8x+3x-2=0

We add all the numbers together, and all the variables

8x^2-5x-2=0

a = 8; b = -5; c = -2;
Δ = b2-4ac
Δ = -52-4·8·(-2)
Δ = 89
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-\sqrt{89}}{2*8}=\frac{5-\sqrt{89}}{16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+\sqrt{89}}{2*8}=\frac{5+\sqrt{89}}{16}
$