Question

Brenda received a gift card for an internet cafe. The cost,y, of renting a computer and using it for x hours at the cafe is shown in the graph below. Which equation represents the same relationship as the graph?

Answer 1

In order to find the equation of the graph, we need to get two points on the graph.

Two points on the graph are points (2, 24) and (4, 33)

The next step is to find the slope of the graph, using the two points above

`\begin{gathered} \text{ slope, m = }(y_2-y_1)/(x_2-x_1) \\ \text{ (x}_1,y_1)=(2,24)_{} \\ (x_2,y_{2_{}})=(4,\text{ 33)} \\ m=(33-24)/(4-2) \\ m=(9)/(2) \\ m=4.5 \end{gathered}`

Then, using slope and one point formula, find the equation of the line

`\begin{gathered} \text{ y-y}_1=m(x-x_1) \\ m=\text{ 4.5, (x}_1,y_1)=(2,24) \\ y-24=4.5(x-2) \\ y-24=4.5x-9 \\ y=4.5x-9+24 \\ y=4.5x+15 \end{gathered}`

The correct answer is y= 4.5x + 15