Answer:
27
Step-by-step explanation:
first we can simplify by dividing by r
[tex] \frac{9 {r}^{2} }{r} = \frac{9 \times r \times r}{r} = 9 \times r \times 1 = 9r[/tex]
the r on the bottom of the fraction will cancel out one of the r's on top, this happens because anything divided by itself is 1, thus r divided by r is 1
finally we can evaluate when r =3,
9r = 9(3) = 27
