3n^2+7.85=90

Solution for 3n^2+7.85=90 equation:

3n^2+7.85=90

We move all terms to the left:

3n^2+7.85-(90)=0

We add all the numbers together, and all the variables

3n^2-82.15=0

a = 3; b = 0; c = -82.15;
Δ = b2-4ac
Δ = 02-4·3·(-82.15)
Δ = 985.8
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{985.8}}{2*3}=\frac{0-\sqrt{985.8}}{6}
=-\frac{\sqrt{}}{6}
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{985.8}}{2*3}=\frac{0+\sqrt{985.8}}{6}
=\frac{\sqrt{}}{6}
$