x2-10x-28=0

Solution for x2-10x-28=0 equation:

x2-10x-28=0

We add all the numbers together, and all the variables

x^2-10x-28=0

a = 1; b = -10; c = -28;
Δ = b2-4ac
Δ = -102-4·1·(-28)
Δ = 212
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:

$\sqrt{\Delta}=\sqrt{212}=\sqrt{4*53}=\sqrt{4}*\sqrt{53}=2\sqrt{53}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-2\sqrt{53}}{2*1}=\frac{10-2\sqrt{53}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+2\sqrt{53}}{2*1}=\frac{10+2\sqrt{53}}{2}
$