n2-21n=0

Solution for n2-21n=0 equation:

n2-21n=0

We add all the numbers together, and all the variables

n^2-21n=0

a = 1; b = -21; c = 0;
Δ = b2-4ac
Δ = -212-4·1·0
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-21}{2*1}=\frac{0}{2}
=0
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+21}{2*1}=\frac{42}{2}
=21
$