Answer:21
Step-by-step explanation:12 times three is 36 and 7 times 3 is 21
Phone card = $20
You need to minus 17.92 from 20 = $2.08
$2.08 / 0.13 = how many minutes
= 16
Number 6 is incorrect. Remember when you see -(-1) that is addition because you are subtracting a negative from a negative so you take the negative sign away and you have a positive. The correct answer to 6 is -75. For number 9 the first thing that you are gonna do is distribute that negative sign to the -12 in parentheses. This will make it a positive 12 which leaves you with
-8+12-31=-27
Next for number 12 you will distribute the - sign onto the -9 in parentheses and the -16 in parentheses. This will leave you with -16+9+16=9
Hope that this helped!
I like to solve these by graphing, so if you graph both of these functions (as shown in the picture below), you look for the intersection between the two graphs, which in this case is
(-2,6).