n1+3(n2)=30

Solution for n1+3(n2)=30 equation:

n1+3(n2)=30

We move all terms to the left:

n1+3(n2)-(30)=0

We add all the numbers together, and all the variables

3n^2+n-30=0

a = 3; b = 1; c = -30;
Δ = b2-4ac
Δ = 12-4·3·(-30)
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-19}{2*3}=\frac{-20}{6}
=-3+1/3
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+19}{2*3}=\frac{18}{6}
=3
$