Simplify each expression.

1. $x^{2}x^{3}x^{2}$

   Hint (a):

   To multiply expressions with a common base, add
   the exponents together.

   Help (a):

   $x^{(2+3+2)}$

   Answer (a):

   $x^7$

2. $\left(xy^{3}z\right)\left(xy\right)$

   Hint (b):

   See part (a).

   Answer (b):

   $x^2y^4z$

3. $5 · t^{2 }· 5^{3 }· t$

   Hint (c):

   See part (a) and (b).