r^2=24-3r

Solution for r^2=24-3r equation:

r^2=24-3r

We move all terms to the left:

r^2-(24-3r)=0

We add all the numbers together, and all the variables

r^2-(-3r+24)=0

We get rid of parentheses

r^2+3r-24=0

a = 1; b = 3; c = -24;
Δ = b2-4ac
Δ = 32-4·1·(-24)
Δ = 105
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{-(3)-\sqrt{105}}{2*1}=\frac{-3-\sqrt{105}}{2}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{105}}{2*1}=\frac{-3+\sqrt{105}}{2}
$