7n(3-n)=0

Solution for 7n(3-n)=0 equation:

7n(3-n)=0

We add all the numbers together, and all the variables

7n(-1n+3)=0

We multiply parentheses

-7n^2+21n=0

a = -7; b = 21; c = 0;
Δ = b2-4ac
Δ = 212-4·(-7)·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*-7}=\frac{-42}{-14}
=+3
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+21}{2*-7}=\frac{0}{-14}
=0
$