X2-14x-1=9

Solution for X2-14x-1=9 equation:

X2-14X-1=9

We move all terms to the left:

X2-14X-1-(9)=0

We add all the numbers together, and all the variables

X^2-14X-10=0

a = 1; b = -14; c = -10;
Δ = b2-4ac
Δ = -142-4·1·(-10)
Δ = 236
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:

$\sqrt{\Delta}=\sqrt{236}=\sqrt{4*59}=\sqrt{4}*\sqrt{59}=2\sqrt{59}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-14)-2\sqrt{59}}{2*1}=\frac{14-2\sqrt{59}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-14)+2\sqrt{59}}{2*1}=\frac{14+2\sqrt{59}}{2}
$