Answer
(a) $A+B$ not defined.
(b) $A-B$ not defined.
(c) \begin{align*}
2A
&=\left[\begin{array}{rrr}{12} & {0} & {6} \\ {-2} & {-8} & {0} \end{array}\right].
\end{align*}
(d) $2A-B$ not defined.
(e) $\frac{1}{2}A+B$ not defined.
Work Step by Step
Given $$
A=\left[\begin{array}{rrr}{6} & {0} & {3} \\ {-1} & {-4} & {0}\end{array}\right], \quad B=\left[\begin{array}{ll}{8} & {-1} \\ {4} & {-3}\end{array}\right]
$$
(a) $A+B$ not defined.
(b) $A-B$ not defined.
(c) \begin{align*}
2A&=2\left[\begin{array}{rrr}{6} & {0} & {3} \\ {-1} & {-4} & {0}\end{array}\right],\\
&=\left[\begin{array}{rrr}{12} & {0} & {6} \\ {-2} & {-8} & {0} \end{array}\right].
\end{align*}
(d)$2A-B$ not defined.
(e) $\frac{1}{2}A+B$ not defined.
