r*r-17*r=60

Solution for r*r-17*r=60 equation:

r*r-17r=60

We move all terms to the left:

r*r-17r-(60)=0

We add all the numbers together, and all the variables

-17r+r*r-60=0

Wy multiply elements

r^2-17r-60=0

a = 1; b = -17; c = -60;
Δ = b2-4ac
Δ = -172-4·1·(-60)
Δ = 529
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{529}=23$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-17)-23}{2*1}=\frac{-6}{2}
=-3
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-17)+23}{2*1}=\frac{40}{2}
=20
$