X*x+16x+39=0

Solution for X*x+16x+39=0 equation:

X*X+16X+39=0

We add all the numbers together, and all the variables

16X+X*X+39=0

Wy multiply elements

X^2+16X+39=0

a = 1; b = 16; c = +39;
Δ = b2-4ac
Δ = 162-4·1·39
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-10}{2*1}=\frac{-26}{2}
=-13
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+10}{2*1}=\frac{-6}{2}
=-3
$