The total cost of a compact disc, including a 6% sales tax, is $14.31 what is the price before tax

$13.50

Step-by-step explanation:

First thing you want to do is find what is 6% of 14.31. You can find this using your calculator and putting the percentage in decimal form then multiplying it by the given amount. 0.06 x 14.31 = ? And then you take that number and subtract it from 14.31.

$13.50

Step-by-step explanation:

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional