Simplify the Expression: 2a+3b-(4b-3a)

We begin by addressing the parenthesis first:

Remember that:

When we multiply a positive number by a negative number, the result will be negative.

When we multiply a negative number by a negative number, the result will be positive.

Hence we obtain the following calculation:

$2a+3b-4b+3a=$

We join together the a coefficients:

$2a+3a=5a$

We then join together the b coefficients:

$3b-4b=-b$

We obtain the following:

$5a-b$