#### Answer

$
a.
\left[ {\begin{array}{cc}
-4 \\
1.5 \\
-16 \\\
\end{array} } \right]
$
$
b.
\left[ {\begin{array}{cc}
1 & 1\\
2.5 & 10 \\
\end{array} } \right]
$

#### Work Step by Step

Add corresponding elements.
a.
$5 - 9 = -4$
$3.2 - 1.7 = 1.5$
$-4.9 - 11.1 = -16$
Subtract corresponding elements.
b.
$ -4 + 5 = 1$
$0 + 1 = 1$
$3 - 0.5= 2.5$
$7 + 3 = 10$