Question

Add : $3\mathrm{xy}+7\mathrm{xy}+9\mathrm{xy}$

Answer 1

We know that, the sum of two or more like terms is another like term, the coefficient of which is the sum of the coefficients of like terms.

So,

$3\mathrm{xy}+7\mathrm{xy}+9\mathrm{xy}=19\mathrm{xy}$

Hence, the sum is $19\mathrm{xy}$ .