Question

What is the y-intercept of the function,represented by the table of values below?

Answer 1

8

Explanation:

So the y-intercept is not given by your table because there is no x that is listed as 0.

But don't fret; we can still find it.

Let's see if the function is linear by seeing if we have the same slope per two points in the table.

For the first pair ( the points (-2,16) and (1,4) ), x increased by 3 and the y decreased by 12 so the slope there is -12/3=-4.

Now looking at the next pair ( the points (1,4) and (2,0) ), x increased by 1 while y decreased by 4 so the slope is -4/1=-4.

So the function appears to be linear.

So the slope-intercept form of a line is y=mx+b where m is slope and b is y-intercept.

We already found the slope from earlier which is m=-4.

So the equation so far is y=-4x+b.

Now to find b, the y-intercept, we need to use a point (x,y) on the line along with y=-4x+b.

Let's see my favorite on the list of points is (2,0).

y=-4x+b with (x,y)=(2,0)

0=-4(2)+b

0=-8+b

8=b

So the y-intercept is 8.