60-139r=12r^2

Solution for 60-139r=12r^2 equation:

60-139r=12r^2

We move all terms to the left:

60-139r-(12r^2)=0

determiningTheFunctionDomain
-12r^2-139r+60=0

a = -12; b = -139; c = +60;
Δ = b2-4ac
Δ = -1392-4·(-12)·60
Δ = 22201
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{22201}=149$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-139)-149}{2*-12}=\frac{-10}{-24}
=5/12
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-139)+149}{2*-12}=\frac{288}{-24}
=-12
$