Answer
a) The required solution is $31x$
b) The required solution is $31\sqrt{2}$
Work Step by Step
(a)
The given expression is,
$21x+10x$
Now, take out the common factors and solve.
$\begin{align}
& 21x+10x=x\left( 21+10 \right) \\
& =31x
\end{align}$
Thus, $21x+10x=$ $31x$.
(b)
The given expression is,
$21\sqrt{2}+10\sqrt{2}$
Now take out the common factors and solve.
$\begin{align}
& 21\sqrt{2}+10\sqrt{2}=\sqrt{2}\left( 21+10 \right) \\
& =31\sqrt{2}
\end{align}$
Thus, $21\sqrt{2}+10\sqrt{2}=$ $31\sqrt{2}$.
