x^2=85.5-5x

Solution for x^2=85.5-5x equation:

x^2=85.5-5x

We move all terms to the left:

x^2-(85.5-5x)=0

We add all the numbers together, and all the variables

x^2-(-5x+85.5)=0

We get rid of parentheses

x^2+5x-85.5=0

a = 1; b = 5; c = -85.5;
Δ = b2-4ac
Δ = 52-4·1·(-85.5)
Δ = 367
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{-(5)-\sqrt{367}}{2*1}=\frac{-5-\sqrt{367}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{367}}{2*1}=\frac{-5+\sqrt{367}}{2}
$