HELP WITH MY DAUGHTERS HOMEWORK

susanne

New member
Joined
Aug 7, 2008
Messages
3
:wink:

I need help please!!! I have no clue.... it as follows

1) IF f(x) = 3xto the second power + 6x - 5...find....


OPTIONS

f(2)
f(-3)
f(0)

2) IF g(x) = 2x + 5(3x-2) ...find..

OPTIONS

G(1)
G(-3)
g(0)
g(x) = 6, x =
g(x) = -2, x+
 
Your daughter should post the work, including what she has tried, and why she seems to be stuck.
 
what work?!!! the teacher didn't show them what to do or how to do it!!! I guess the math criteria in GA was set up to fail...not text books nothing!
 
I appreciate your input. I will try and find the solution from another place.

peace out
 
You might google "functions" and see if there is some explanations that will help you. As for your particular problem...

1) IF \(\displaystyle f(x) = 3x^2 + 6x - 5\)

If you were asked to find f(1) you would simply plug the 1 into the the equation in place of the x, then evaluate.

\(\displaystyle f(1) = 3(1)^2 + 6(1) - 5 = 3 + 6 - 5 = 4\)

If you were asked to find f(-2) it would go like this...

\(\displaystyle f(-2) = 3(-2)^2 + 6(-2) - 5 = 3(4) + (-12) - 5 = 12 - 12 -5 = -5\)

Hope that helps.
 
susanne said:
what work?!!! the teacher didn't show them what to do or how to do it!!! I guess the math criteria in GA was set up to fail...not text books nothing!
I'm sorry to hear that your daughter is being tested on information that has not been covered in class, and for which she has no book, papers, notes, or any other instructional information. This school must keep you and your daughter very busy, since she has to teach herself all the material in all of her courses, with of course hours of daily help from you.

Unfortunately, we cannot provide the years of missing classroom instruction within this environment. Your school should, under the "No Child Left Behind" legislation, be obligated to provide access to tutoring (at no cost to you) to provide the necessary (but currently withheld) instructional materials and time. Please conference immediately with the guidance office or some other aspect of the administration of your daughter's school, to obtain the resources, funded by the Federal government, to replace the education that is currently being withheld. You may also find it helpful to contact local news media (to expose this gross negligence) and legal counsel (for the class-action suit that no doubt thousands of parents in your district will want to join).

Our best wishes to you and your daughter.

Eliz.
 
If f(x) = 3x^2 + 6x - 5 and they ask for you to solve f(2), you just simply plug 2 in for x and see what answer you get:


f(x) = 3x^2 + 6x - 5

f(2) = 3(2)^2 + 6(2) - 5
f(2) = 3(2*2) + 12 - 5
f(2) = 3(4) + 12 - 5
f(2) = 12 + 12 - 5
f(2) = 19

Unless I made some silly mistake.

Then if they give you a function, g(x) = 2x + 5(3x - 2) and tell you what it equals:

g(x) = 6
or
g(x) = -2

they are asking you to work backwards (in a sense) and solve for x when g(x) equals a set value such as 6 or -2. So...

g(x) = 6 = 2x + 5(3x - 2)
6 = 2x + 5(3x - 2)
6 = 2x + 15x - 10
6 = 17x - 10
6 + 10 = 17x - 10 + 10
16 = 17x
16/17 = (17x)/17
16/17 = 0.94117647059 = x

http://tinyurl.com/5z4lsq

When a problem asks you to find f(a number) or g(a number), it's basically just saying to evaluate the function at "a number" by simply plugging in "a number" for the variable of the function. In both of your cases, the variable was "x". However, if they tell you what the function equals, but they don't tell you what x is, they probably want you to figure out what x equals. They will write this like:

If g(x) = 2x + 5(3x - 2)

g(x) = 6, x = ?
or
g(x) equals 6, so then x equals ?
or
g(x) equals 6, solve for x

Hope that helps - I have a feeling I might have confused you though... sorry!
 
Top