Simplify each expression.

1. $\frac { 3 ^ { 2 } \cdot 5 ^ { 3 } \cdot 8 } { 3 \cdot 5 ^ { 3 } \cdot 8 }$ 

   Hint (a):

   Recall that when you divide a number by itself, the quotient is $1$. Can you find any factors that are in both the numerator and the denominator?

   More Help 1(a):

   You can rewrite the expression.

   $\frac{3\cdot3\cdot5\cdot5\cdot5\cdot8}{3\cdot5\cdot5\cdot5\cdot8}$

   More Help 2(a):

   There are three $5$'s on the top and on the bottom, which may be removed by division. Similarly, there are $8$'s and $3$'s that can be removed.

   Answer (a):

   $3$

2. $\left(3x\right)^{4}$ 

   Hint (b):

   Rewrite the expression and simplify.
   $\left(3x\right)\left(3x\right)\left(3x\right)\left(3x\right)$

   Answer (b):

   $81x^{4}$

3. $3 ^ { 3 } \cdot 3 ^ { 5 } \cdot ( \frac { 1 } { 3 } ) ^ { 2 }$ 

   Hint (c):

   You can rewrite this expression as:

   $\frac{3^{3}3^{5}}{3^{2}}$

4. $\frac { 7 ^ { 4 } \cdot 9 ^ { 2 } } { 9 ^ { 3 } \cdot 7 ^ { 2 } }$  

   Hint (d):

   See (a).