Answer
\begin{align*}
U+V&=2i\\
U-V&=2j\\
3U+2V&=5i+j.
\end{align*}
Work Step by Step
We have $U=i+j, V=i-j.$
First find $U+V$,
\begin{align*}
U+V&=(i+j)+(i-j)\\
&=i+j+i-j\\
&=2i.
\end{align*}
Hence, $U+V=2j.$
Then find $U-V$,
\begin{align*}
U-V&=(i+j)-(i-j)\\
&=i+j-i+j\\
&=2j.
\end{align*}
Hence, $U-V=2j.$
In the end find,
\begin{align*}
3U+2V&=3(i+j)+2(i-j)\\
&=(3i+3j)+(2i-2j)\\
&=3i+3j+2i-2j\\
&=5i+j.
\end{align*}
