-3(r-3)r=-1

Solution for -3(r-3)r=-1 equation:

-3(r-3)r=-1

We move all terms to the left:

-3(r-3)r-(-1)=0

We add all the numbers together, and all the variables

-3(r-3)r+1=0

We multiply parentheses

-3r^2+9r+1=0

a = -3; b = 9; c = +1;
Δ = b2-4ac
Δ = 92-4·(-3)·1
Δ = 93
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{-(9)-\sqrt{93}}{2*-3}=\frac{-9-\sqrt{93}}{-6}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+\sqrt{93}}{2*-3}=\frac{-9+\sqrt{93}}{-6}
$