Expert: Sherman D. - 3/17/2004

Question
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Followup To
Question -
Hi...I have a question from my Finite Math course...I actually need help with all the questions of this type because I have no idea how to get the right answers for them:

If...F(t)=4t+7, find:

F(3+h)-F(3)/h

THe way they write it in my textbook, the "h" is actually under the rest of the equation, like a fraction.  Hope you can help me with this.  I don't understand the method of howw to do these types of equations.  Thanks, bye.
Answer -
I only have one thing to say, if you have any more questions like this, BRING THEM ON.

F(t) = 4t + 7

if by this you mean

{F(3 + h) - F(3)}/h

then

F(3 + h) = 4(3 + h) + 7
F(3 + h) = 12 + 4h + 7
F(3 + h) = 4h + 19

F(3) = 4(3) + 7
F(3) = 12 + 7
F(3) = 19

so

{F(3 + h) - F(3)}/h

becomes

{(4h + 19) - 19}/h

{4h + 19 - 19}/h

{4h}/h

the "h"s cancel out, so the answer is

4


Thanx for the help...I just need to know, How did you do that? explain?

Answer
as explained in the other problem you sent.

With function problems all you have to do is replace "t" with the value that you are given, the value that is in (), also keep in mind that F(3 + h) and F(3) are to different problems since they are 2 different values.

F(t) = 4t + 7
F(3 + h) = 4(3 + h) + 7
F(3) = 4(3) + 7

do you see how i replaced "t" with "3 + h" for one problem, then i replaced "t" with "3" for the other problem, then i worked those out and i got 4h/h, which becomes 4 to be your answer.

If you think this is hard, wait until you get to problems like f(g(x)), (f * g), (f/g), (f^g), etc... and if you run into those kinds of problems, just send them my way, and i will show you how they are done, and if you like, i will try to explain how they are done.

If you want me to explain, then you can only give me like 1 or 2 at a time, but if you want me to just show you how they are done since you finally understand them. Then you can send me a max of 5 or 10, depending on how much i have to do.