#### Answer

$a_1=\frac{3}{2}$
$d=\frac{3}{4}$

#### Work Step by Step

In an arithmetic sequence, the common difference can be calculated as the difference of any two subsequent terms:
$d=a_2-a_1=\frac{9}{4}-\frac{3}{2}=\frac{3}{4}$
The first term is:
$a_1=\frac{3}{2}$.