2n^2+9n-10=90

Solution for 2n^2+9n-10=90 equation:

2n^2+9n-10=90

We move all terms to the left:

2n^2+9n-10-(90)=0

We add all the numbers together, and all the variables

2n^2+9n-100=0

a = 2; b = 9; c = -100;
Δ = b2-4ac
Δ = 92-4·2·(-100)
Δ = 881
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{-(9)-\sqrt{881}}{2*2}=\frac{-9-\sqrt{881}}{4}
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+\sqrt{881}}{2*2}=\frac{-9+\sqrt{881}}{4}
$