Question

Lisa reads an equal number of pages of a book every week. The graph below shows the number of pages of the book left to read, y, after x weeks: A graph titled Lisas Book Reading shows Number of Weeks on the x-axis and Number of Pages Left on the y-axis. The scale on the x-axis shows numbers from 0 to 6 at increments of 1, and the scale on the y-axis shows numbers from 0 to 350 at increments of 50. A straight line joins the ordered pairs 0, 250 and 1, 200 and 2, 150 and 3, 100 and 4, 50 and 5, 0. Which equation best models the relationship between x and y? y = −50x + 250 y = −5x + 50 y = −50x + 350 y = −5x + 250

Answer 1

Answer: $y=-50x+250$

Step-by-step explanation:

From the graph the slope of the graph is given by using points (0,250) and (1,200)

Slope (m)=$=\frac{y_2-y_1}{x_2-x_1}=\frac{200-250}{1-0}=-50$

For slope 'm' and any point ()$(x_1,y_1)$, the equation of the line is given by

$(y-y_1)=m(x-x_1)$

So for m=-50, and point (0,250), the equation of line is given by

$(y-250)=-50(x-0)\\\Rightarrow\ y-250=-50x\\\Rightarrow\ y=-50x+250$

Answer 2

The answer is A, because i took this test and got the right answer.