X2-25x+156=0

Solution for X2-25x+156=0 equation:

X2-25X+156=0

We add all the numbers together, and all the variables

X^2-25X+156=0

a = 1; b = -25; c = +156;
Δ = b2-4ac
Δ = -252-4·1·156
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-1}{2*1}=\frac{24}{2}
=12
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+1}{2*1}=\frac{26}{2}
=13
$