-x^2-7x-9=0

Solution for -x^2-7x-9=0 equation:

-x^2-7x-9=0

We add all the numbers together, and all the variables

-1x^2-7x-9=0

a = -1; b = -7; c = -9;
Δ = b2-4ac
Δ = -72-4·(-1)·(-9)
Δ = 13
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{-(-7)-\sqrt{13}}{2*-1}=\frac{7-\sqrt{13}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+\sqrt{13}}{2*-1}=\frac{7+\sqrt{13}}{-2}
$