100n^2-7=9

Solution for 100n^2-7=9 equation:

100n^2-7=9

We move all terms to the left:

100n^2-7-(9)=0

We add all the numbers together, and all the variables

100n^2-16=0

a = 100; b = 0; c = -16;
Δ = b2-4ac
Δ = 02-4·100·(-16)
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-80}{2*100}=\frac{-80}{200}
=-2/5
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+80}{2*100}=\frac{80}{200}
=2/5
$