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Question 811973: hey just a simple question on relations and functions.im working out of a text book a and worksheet. my papers instructions are:
To evaluate each function for the given value of x, and write the input x and the output f(x) as an ordered pair.
for example. F(x) = -3x+2 for x = 3
F(x) = 1/2 x -1 for x = -2
the lesson in the book is just didnt click for me. here is the lesson in the book:
The Area of a square tile is a function of the length of a side of the square. write a function rule for the area of a square. evaluate the function for a square tile with the side legth of 3.5in
Relate: area of a square IS (side length)^2
Define: Let[s] = the length of one side of the square tile, then A(s)= the area of the square tile
Write: A(s) = s^2
A(3.5) = (3.5)2 Substitute 3.5 for S
= 12.25 Simplify
The area of a square tile with side length 3.5 in is 12.25 in ^2
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that lesson really didnt explain to me how to complete the 2 questions at the top of the page. i know what a function is, i know what and how to find the domain and range. i know how to put it on a graph. and i do realize that F(x) means F of x, not F times x.
maybe you can help explain how to do a the two problems at the top and i can start to finish my paper. Thank you!
Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website! Here is the part of the lesson you missed
Write: A(s) = s^2
A(3.5) = (3.5)2 Substitute 3.5 for S
[Substitute 3.5 for S]
In your two problems substitute the number for x
The easiest way is to think of F(x) as y
y = -3x+2 for x = 3
F(x) = -3x+2 for x = 3
now just plug in 3 every time you see x
F(3) = -3*3+2
f(3) = (-3*3)+2
F(3)=-9+2
F(3)=-7
ordered pair (3,-7)
y= 1/2 x -1 for x = -2
F(x) = 1/2 x -1 for x = -2
now just plug in =2 every time you see x
F(-2) = 1/2 *(-2) -1
F(-2)=-1-1
F(-2)=-2
ordered pair (-2,-2)
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