#### Answer

a) $9.45x$
b) $9+4h$
c) $\frac{2}{3n}$

#### Work Step by Step

a) Use the Associative Property of Multiplication:
$2.1(4.5x)=(2.1\times4.5)x=9.45x$
b) Use the Commutative Property of Addition:
$6+(4h+3)=6+(3+4h)$, then use the Associative property of Addition:
$6+(3+4h)=(6+3)+4h=9+4h$
c) Rewrite the equation like this:
$\frac{8\times m}{12\times m\times n}$, cancel out the m's:
$\frac{8\times m}{12\times m\times n}=\frac{8}{12\times n}$
Rewrite the equation:
$\frac{8}{12\times n}=\frac{4\times 2}{4\times3n}$, cancel out the 4s and you will be left with:
$\frac{2}{3n}$