A long distance phone charge of $1.40 for 10 min or 4.50 for 45 min. which is better

$4.50 for 45min is better.

Step-by-step explanation:

The fee per min for phone charge of $1.40 for 10 min: 1.40/10 = $0.14/min

The fee per min for phone charge of $4.50 for 45 min: 4.50/45 = $0.1/min

$0.14/ min > $0.1/min

4.50 for 45min is better.

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.