(x^2)-(3x)-28=171

Solution for (x^2)-(3x)-28=171 equation:

(x^2)-(3x)-28=171

We move all terms to the left:

(x^2)-(3x)-28-(171)=0

We add all the numbers together, and all the variables

x^2-3x-199=0

a = 1; b = -3; c = -199;
Δ = b2-4ac
Δ = -32-4·1·(-199)
Δ = 805
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{-(-3)-\sqrt{805}}{2*1}=\frac{3-\sqrt{805}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+\sqrt{805}}{2*1}=\frac{3+\sqrt{805}}{2}
$