2n^2+15n-20=-3n^2

Solution for 2n^2+15n-20=-3n^2 equation:

2n^2+15n-20=-3n^2

We move all terms to the left:

2n^2+15n-20-(-3n^2)=0

We get rid of parentheses

2n^2+3n^2+15n-20=0

We add all the numbers together, and all the variables

5n^2+15n-20=0

a = 5; b = 15; c = -20;
Δ = b2-4ac
Δ = 152-4·5·(-20)
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-25}{2*5}=\frac{-40}{10}
=-4
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+25}{2*5}=\frac{10}{10}
=1
$