Answer
a. $\left[\begin{array}{ll}
9 & 10\\
3 & 9
\end{array}\right]$
b. $\left[\begin{array}{ll}
-1 & -8\\
3 & -5
\end{array}\right]$
c. $\left[\begin{array}{ll}
-16 & -4\\
-12 & -8
\end{array}\right]$
d. $\left[\begin{array}{ll}
22 & 21\\
9 & 20
\end{array}\right]$
Work Step by Step
a.
$A+B=\left[\begin{array}{ll}
4+5 & 1+9\\
3+0 & 2+7
\end{array}\right]=\left[\begin{array}{ll}
9 & 10\\
3 & 9
\end{array}\right]$
b.
$A-B=\left[\begin{array}{ll}
4-5 & 1-9\\
3-0 & 2-7
\end{array}\right]=\left[\begin{array}{ll}
-1 & -8\\
3 & -5
\end{array}\right]$
c.
$-4A=\left[\begin{array}{ll}
-4(4) & -4(1)\\
-4(3) & -4(2)
\end{array}\right]=\left[\begin{array}{ll}
-16 & -4\\
-12 & -8
\end{array}\right]$
d.
$3A+2B=\left[\begin{array}{ll}
3(4)+2(5) & 3(1)+2(9)\\
3(3)+2(0) & 3(2)+2(7)
\end{array}\right]=\left[\begin{array}{ll}
22 & 21\\
9 & 20
\end{array}\right]$
