To answer this question, we have that the cost of the item is represented by c, and we need to add to this cost the 9% sales tax.
Therefore, to find the expression that gives the price of clothes after including the sales tax is as follows:
• The 9% sales tax is given by:
[tex]\begin{gathered} 9\%=\frac{9}{100}=0.09 \\ \frac{9}{100}c=0.09c \end{gathered}[/tex]We can see that the tax is 9% of the cost of the clothes. Now, we have to add this tax to the original cost. If the original cost of the clothes is c, then we have:
[tex]\begin{gathered} P=c+0.09c \\ P=c(1+0.09) \\ P=c(1.09) \\ P=1.09c_{} \end{gathered}[/tex]Therefore, in summary, the expression that gives the price of clothes after including the sales tax is:
[tex]P=1.09c[/tex][Second option.]
