3n2-0.75=90

Solution for 3n2-0.75=90 equation:

3n^2-0.75=90

We move all terms to the left:

3n^2-0.75-(90)=0

We add all the numbers together, and all the variables

3n^2-90.75=0

a = 3; b = 0; c = -90.75;
Δ = b2-4ac
Δ = 02-4·3·(-90.75)
Δ = 1089
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1089}=33$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-33}{2*3}=\frac{-33}{6}
=-5+1/2
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+33}{2*3}=\frac{33}{6}
=5+1/2
$