-24=(-24-r)r

Solution for -24=(-24-r)r equation:

-24=(-24-r)r

We move all terms to the left:

-24-((-24-r)r)=0

We add all the numbers together, and all the variables

-((-1r-24)r)-24=0


We calculate terms in parentheses: -((-1r-24)r), so:

(-1r-24)r

We multiply parentheses

-1r^2-24r

Back to the equation:

-(-1r^2-24r)


We get rid of parentheses

1r^2+24r-24=0

We add all the numbers together, and all the variables

r^2+24r-24=0

a = 1; b = 24; c = -24;
Δ = b2-4ac
Δ = 242-4·1·(-24)
Δ = 672
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{672}=\sqrt{16*42}=\sqrt{16}*\sqrt{42}=4\sqrt{42}$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(24)-4\sqrt{42}}{2*1}=\frac{-24-4\sqrt{42}}{2}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(24)+4\sqrt{42}}{2*1}=\frac{-24+4\sqrt{42}}{2}
$