s2-11s-28=0

Solution for s2-11s-28=0 equation:

s2-11s-28=0

We add all the numbers together, and all the variables

s^2-11s-28=0

a = 1; b = -11; c = -28;
Δ = b2-4ac
Δ = -112-4·1·(-28)
Δ = 233
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-11)-\sqrt{233}}{2*1}=\frac{11-\sqrt{233}}{2}
$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-11)+\sqrt{233}}{2*1}=\frac{11+\sqrt{233}}{2}
$