Answer:
Equation: y = 2.5x + 5
Cost: $30
Explanation:
The equation of a line can be calculated using the following:
[tex]y=m(x-x_1)+y_1[/tex]Where m is the slope and it is calculated as:
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]Where (x1, y1) and (x2, y2) are points on the line. If we take the number of lines of the ad as x and the Cost as y, then the table gives us two points (3, 12.50) and (5, 17.50)
So, replacing (x1, y1) by ( 3, 12.50) and (x2, y2) by (5, 17.50), we get that the slope and the equation are:
[tex]m=\frac{17.50-12.50}{5-3}=\frac{5}{2}[/tex][tex]\begin{gathered} y=\frac{5}{2}(x-3)+12.50 \\ y=\frac{5}{2}x-\frac{5}{2}\cdot3+12.50 \\ y=\frac{5}{2}x-\frac{15}{2}+12.50 \\ y=2.5x+5 \end{gathered}[/tex]Now, to find the cost of an ad that is 10 lines long, we need to replace x by 10 and calculated y as:
[tex]\begin{gathered} y=2.5(10)+5 \\ y=25+5 \\ y=30 \end{gathered}[/tex]Therefore, the cost of the ad is $30
