-x-5x+(-3x2)-9-2x+7=0

Solution for -x-5x+(-3x2)-9-2x+7=0 equation:

-x-5x+(-3x^2)-9-2x+7=0

We add all the numbers together, and all the variables

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

We get rid of parentheses

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

a = -3; b = -8; c = -2;
Δ = b2-4ac
Δ = -82-4·(-3)·(-2)
Δ = 40
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{40}=\sqrt{4*10}=\sqrt{4}*\sqrt{10}=2\sqrt{10}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-2\sqrt{10}}{2*-3}=\frac{8-2\sqrt{10}}{-6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+2\sqrt{10}}{2*-3}=\frac{8+2\sqrt{10}}{-6}
$