x^2+14x-9=3

Solution for x^2+14x-9=3 equation:

x^2+14x-9=3

We move all terms to the left:

x^2+14x-9-(3)=0

We add all the numbers together, and all the variables

x^2+14x-12=0

a = 1; b = 14; c = -12;
Δ = b2-4ac
Δ = 142-4·1·(-12)
Δ = 244
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:

$\sqrt{\Delta}=\sqrt{244}=\sqrt{4*61}=\sqrt{4}*\sqrt{61}=2\sqrt{61}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(14)-2\sqrt{61}}{2*1}=\frac{-14-2\sqrt{61}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(14)+2\sqrt{61}}{2*1}=\frac{-14+2\sqrt{61}}{2}
$