Question

What has to be added to $(a+b)$ to get $(3a+2b)$?

• A. $2a+3b$
• B. $2a+b$
• C. $4a+3b$
• D. $-2a-b$

Answer 1

The correct option is B

$2a+b$

Let the expression that is to be added to $a+b$ be $X$

Then, $(a+b)+X$ = $3a+2b$
or, $X$ = $(3a+2b)-(a+b)$
So, $X$ =$3a+2b-a-b$

i.e. $X$ =$3a-a+2b-b$
Therefore, $X$ =$2a+b$