It would cost $132. 7+7+15+15X3=132
X^2(2y+5)=240
x^2(2(5)+5)=240
x^2+(10+5)=240
x^2+15=240
minus 15 both sides
x^2=225
sqrt both sides
x=15
First you will get the sale price.
you need to convert the percentage to a decimal and to do that you move the decimal over twice:
30% = .30
then multiply the CD price by the decimal
$14.00 X .30 = $4.20
then you have the sales price but you need to find the tax price
to do that you move the decimal of the tax percentage over twice
7% = .07%
then multiply by the price after the sale included
.07 X $4.20 = $0.29
you have how much the tax would be
to get the total price you add the tax to the sales price
$0.29 + $4.20 = $4.42
the price you would be paying for this CD including tax is $4.42