X^2-18x+49=0

Solution for X^2-18x+49=0 equation:

X^2-18X+49=0

a = 1; b = -18; c = +49;
Δ = b2-4ac
Δ = -182-4·1·49
Δ = 128
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:

$\sqrt{\Delta}=\sqrt{128}=\sqrt{64*2}=\sqrt{64}*\sqrt{2}=8\sqrt{2}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-8\sqrt{2}}{2*1}=\frac{18-8\sqrt{2}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+8\sqrt{2}}{2*1}=\frac{18+8\sqrt{2}}{2}
$