Posted by **Amy** on Wednesday, December 8, 2010 at 11:15pm.

Can anyone help with the following problem please...Thank u so much

Let f(x) =|9x|. For the area above the x-axis and between the lines x= -9 and x=18

a. draw and label a sketch with

the area shaded

b. find the area of the region in

the xy-plane under the graph

of f(x)

- Pre-Calc -
**MathMate**, Wednesday, December 8, 2010 at 11:36pm
For this kind of problem, it is always desirable to make a sketch within the limits of the domain, from x=-9 to 18.

See:

http://img510.imageshack.us/img510/2928/1291868155.png

Using the formula for the area of a triangle as:

Area = (1/2)base*height

You can find the areas of the two triangles between the function and the x-axis.

If you need further help, don't hesitate to post.

- Pre-Calc -
**Reiny**, Thursday, December 9, 2010 at 12:19am
Amy, please check to see if your question has been answered before posting the same question again.

you asked the same question with only a small change yesterday,

http://www.jiskha.com/display.cgi?id=1291781963

MathMate has gone to some length to answer it again, even creating a picture for you.

make a note of your post by jotting down the time of the first posting, even though it moves off the page, it is then rather easy to find

- Pre-Calc -
**Amy**, Thursday, December 9, 2010 at 12:30am
Thank you for your help

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