r^2-17r=30=

Solution for r^2-17r=30= equation:

r^2-17r=30=

We move all terms to the left:

r^2-17r-(30)=0

a = 1; b = -17; c = -30;
Δ = b2-4ac
Δ = -172-4·1·(-30)
Δ = 409
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-17)-\sqrt{409}}{2*1}=\frac{17-\sqrt{409}}{2}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-17)+\sqrt{409}}{2*1}=\frac{17+\sqrt{409}}{2}
$