Question

Question 2
$\frac{n}{2}-\frac{3n}{4}+\frac{5n}{6}=21$

Answer 1

$\frac{n}{2}-\frac{3n}{4}+\frac{5n}{6}=21$
$\Rightarrow \frac{6n-9n+10n}{12}=21\Rightarrow \frac{7n}{12}=21$
$\Rightarrow n=\frac{21\times 12}{7}\Rightarrow n=36$
To check:
$\frac{n}{2}-\frac{3n}{4}+\frac{5n}{6}=21\Rightarrow \frac{36}{2}-\frac{3\times 36}{4}+\frac{5\times 36}{6}=21$
$\Rightarrow 18-27+30=21\Rightarrow 21=21$
$\Rightarrow LHS.=R.H.S$
Therefore, it is correct.