According to the question, the store is giving 15% off sales on all items. That means there will be a reduction of 15% in sale price of each item.
Let [tex]x[/tex] represent the original price of an item.
15% of the original price[tex]=\frac{15}{100} \times x=0.15x[/tex]
The sale price of an item in the store will now reduce by [tex]0.15x[/tex]. This means that;
[tex]Sale\: Price =Original-0.15(Original)[/tex]
But [tex]x[/tex] is the original price, therefore we can substitute[tex]x[/tex], wherever we see original. This gives us;
[tex]Sale\: Price=x-0.15x[/tex]
Since sale price is expressed in terms of [tex]x[/tex], we can also write it as a function of [tex]x[/tex]. That is,
[tex]f(x)=x-0.15x[/tex]
Therefore the correct answers are
[tex]f(x)=x-0.15x[/tex]
and
[tex]Sale\: Price=Original-0.15(Original)[/tex]
