Answer
$r=9.11,-0.11$
Work Step by Step
$3r^2-27r=3$
or, $r^2-9r=1$
Compare it with the standard form of quadratic equation $ax^2+bx+c$, we have $a=1, b=-9$
To complete the square, add $\dfrac{81}{4}$ on both sides.
$r^2-9r+\dfrac{81}{4}=1+\dfrac{81}{4}$
$\implies (r-\dfrac{9}{2})^2=\dfrac{85}{4}$
$\implies (r-4.5)^2=21.25$
$\implies (r-4.5)=4.61$
and
$\implies (r-4.5)=-4.61$
or, $r=9.11,-0.11$
