Question

Can somebody find the average rate of change?

y = (x-1)^2 -3

Answer 1

Here is a picture of the graph:

Answer 2

I need to find the average rate of change from x=-1 to x=1

Answer 3

@phi

Answer 4

you want change in y divided by change in x
find y at x=-1, and y at x=1
now you have two (x,y) points that you can use

Answer 5

I don't understand @phi

Answer 6

can you find the y value when x=-1 using
y = (x-1)^2 -3
?

Answer 7

Y would equal 1

Answer 8

Y=1

Answer 9

ok, so you have (-1,1) as a point on the curve
now y when x=+1

Answer 10

Y=-3?

Answer 11

so (1,-3) is another point on the curve

now find the slope between those two points. That is the average rate of change between the two points.

Answer 12

Here is a picture

Answer 13

Is the slope 2? The picture is confusing me...

Answer 14

you have two points (-1,1) and (1,-3)
find the change in y divided by the change in x
can you do that ?

Answer 15

-1,-1/3?

Answer 16

using (-1,1) and (1,-3)
the change in y is 1 - (-3) = 1 + 3 = 4
the change in x is -1 - 1 = -2

change in y divided by change in x is 4/-2 = -2

Answer 17

that means that on average, your curve goes down 2 steps for every step to the right, between those two points.

Answer 18

Oh, I did (-1,1) / (1,-3)

Answer 19

I see you're a moderator now

Answer 20

If this stuff is unclear, see
http://www.khanacademy.org/math/cc-eighth-grade-math/cc-8th-relationships-functions/cc-8th-slope/v/slope-of-a-line-2
and his other videos on how to find the slope between two points.

Answer 21

Thank you so much Phi