8n2+7n-15=-7

Solution for 8n2+7n-15=-7 equation:

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

We move all terms to the left:

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

We add all the numbers together, and all the variables

8n^2+7n-8=0

a = 8; b = 7; c = -8;
Δ = b2-4ac
Δ = 72-4·8·(-8)
Δ = 305
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{-(7)-\sqrt{305}}{2*8}=\frac{-7-\sqrt{305}}{16}
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+\sqrt{305}}{2*8}=\frac{-7+\sqrt{305}}{16}
$