x2+18x=25

Solution for x2+18x=25 equation:

x2+18x=25

We move all terms to the left:

x2+18x-(25)=0

We add all the numbers together, and all the variables

x^2+18x-25=0

a = 1; b = 18; c = -25;
Δ = b2-4ac
Δ = 182-4·1·(-25)
Δ = 424
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:

$\sqrt{\Delta}=\sqrt{424}=\sqrt{4*106}=\sqrt{4}*\sqrt{106}=2\sqrt{106}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-2\sqrt{106}}{2*1}=\frac{-18-2\sqrt{106}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+2\sqrt{106}}{2*1}=\frac{-18+2\sqrt{106}}{2}
$