8n^2+7n-15=-7n

Solution for 8n^2+7n-15=-7n equation:

8n^2+7n-15=-7n

We move all terms to the left:

8n^2+7n-15-(-7n)=0

We get rid of parentheses

8n^2+7n+7n-15=0

We add all the numbers together, and all the variables

8n^2+14n-15=0

a = 8; b = 14; c = -15;
Δ = b2-4ac
Δ = 142-4·8·(-15)
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(14)-26}{2*8}=\frac{-40}{16}
=-2+1/2
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(14)+26}{2*8}=\frac{12}{16}
=3/4
$