2n^2-5=30

Solution for 2n^2-5=30 equation:

2n^2-5=30

We move all terms to the left:

2n^2-5-(30)=0

We add all the numbers together, and all the variables

2n^2-35=0

a = 2; b = 0; c = -35;
Δ = b2-4ac
Δ = 02-4·2·(-35)
Δ = 280
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{280}=\sqrt{4*70}=\sqrt{4}*\sqrt{70}=2\sqrt{70}$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{70}}{2*2}=\frac{0-2\sqrt{70}}{4}
=-\frac{2\sqrt{70}}{4}
=-\frac{\sqrt{70}}{2}
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{70}}{2*2}=\frac{0+2\sqrt{70}}{4}
=\frac{2\sqrt{70}}{4}
=\frac{\sqrt{70}}{2}
$