Question

I need a helping hand please

Joseph compared the graphs of two functions.

The first function was f(x)=−2x+6.
The second function fits the values in the table:
x 2 5 8 11
y 2 -4 -10 -16
What is the distance between the y-intercepts of the two functions? To earn full credit, show your work using a method explained in the Orientation.

Answer 1

There is no separation (distance) between the first y-intercept (6) and the second (6).

Explanation:

We'll assume that the table shows points on a straight line.

If we go from x = 2 to x = 8 (an increase of 6), the corresponding y values go from y =2 to y = -10 (a decrease of 12). Thus, the slope of the line represented by the table is

m = rise / run = -12/6, or m = -2.

We need to find the equation of the line represented by the table, so that we can know the y-intercept. Start with y = mx + b and substitute -2 for m:

y = -2x + b. We arbitrarily choose an ordered pair from the table, such as (11, -16). Here we substitute 11 for x and -16 for y:

-16 = -2(11) + b, or

-16 = -22 + b, which yields b = 6.

This is the same y-intercept as the '6' in the given f(x) = -2x + 6. So: There is no separation (distance) between the first y-intercept (6) and the second (6).