Question

Subtract $5mn+9m+8n$ from $16m+7n+12mn$.

• A. $7m+n+7mn$
• B. $7m-n+7mn$
• C. $m-n+7mn$
• D. $7m-n+mn$

Answer 1

The correct option is B $7m-n+7mn$

$\underset{–}{\text{Horizontal Method:}}$
We need to subtract, $5mn+9m+8n$ from $16m+7n+12mn$, i.e.,
$(16m+7n+12mn)$
$-(5mn+9m+8n)$
Combining the like terms together:

$=(16m-9m)+(7n-8n)$
$+(12mn-5mn)$
Now, subtracting the like terms:

$=7m+(-n)+7mn$

$=7m-n+7mn$

The value obtained when $5mn+9m+8n$ is subtracted from $16m+7n+12mn$ is $\underset{–}{7m-n+7mn}.$

$\underset{–}{\text{Column Method:}}$
In this method, first we need to arrange the like terms parallely and then we can subtract the expression.
This can be shown as:

The value obtained when $5mn+9m+8n$ is subtracted from $16m+7n+12mn$ is $\underset{–}{7m-n+7mn}.$

Therefore, option (b.) is the correct answer.