X^2+1+x+2=81

Solution for X^2+1+x+2=81 equation:

X^2+1+X+2=81

We move all terms to the left:

X^2+1+X+2-(81)=0

We add all the numbers together, and all the variables

X^2+X-78=0

a = 1; b = 1; c = -78;
Δ = b2-4ac
Δ = 12-4·1·(-78)
Δ = 313
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-\sqrt{313}}{2*1}=\frac{-1-\sqrt{313}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{313}}{2*1}=\frac{-1+\sqrt{313}}{2}
$