x2+21x+68=0

Solution for x2+21x+68=0 equation:

x2+21x+68=0

We add all the numbers together, and all the variables

x^2+21x+68=0

a = 1; b = 21; c = +68;
Δ = b2-4ac
Δ = 212-4·1·68
Δ = 169
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{169}=13$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-13}{2*1}=\frac{-34}{2}
=-17
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+13}{2*1}=\frac{-8}{2}
=-4
$