n2-(n-7)=12

Solution for n2-(n-7)=12 equation:

n2-(n-7)=12

We move all terms to the left:

n2-(n-7)-(12)=0

We add all the numbers together, and all the variables

n^2-(n-7)-12=0

We get rid of parentheses

n^2-n+7-12=0

We add all the numbers together, and all the variables

n^2-1n-5=0

a = 1; b = -1; c = -5;
Δ = b2-4ac
Δ = -12-4·1·(-5)
Δ = 21
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{-(-1)-\sqrt{21}}{2*1}=\frac{1-\sqrt{21}}{2}
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{21}}{2*1}=\frac{1+\sqrt{21}}{2}
$