any1 know how to solve these

Discussion in 'Off Topic' started by *jessica-123 (01), Dec 14, 2011.

  1. Find the f(g(x)) and g(f(x)) (algebra 2)

    1.f(x)=x 1 and g(x)=2x-5
    2.f(x)= xsquare and g(x)=x-1
    3.f(x)=2x-8 and g(x)=xsquare-2

    Please help me with this stupid thing!
     
  2. Maybe you should pay attention I class :|

    You'll know how to do these then.
     
  3. F(g(x)) or however you wanna type it is just plugging the g(x) equation in for the x in your f(x) equation.
     
  4. I know and I do pay attention but the teacher make no sense like so far everybody is failing that class.
     
  5. I'm in 6th grade...
     
  6. I get that part az but I don't know how to put it together
     
  7. (x-1)^2 is what f(g(x)) would be for the second one. G(f(x)) is just plugging in f(x) as the x in the g(x) equation.
     
  8. Then ask questions! :)
     
  9. I did but he still makes no sense, oh thanks az, I'm in ninth grade Shirley...... I watch a YouTube and understand it lol
     
  10. There's examples in the book...


    18 nCr 22
     
  11. Very true. We even have answers in the back of our book...
     
  12. Yes my textbook aswell, but only the odd page numbers  i think I learned a little bit of trig. In my algebra one class o_O
     
  13. YouTube is a good tool if your teacher is bad which is good that you are using. Does your teacher have tutoring? Even if your teacher is bad, if you can get him with you in tutoring, it is typically more favorable conditions as there are less people and it's easier to ask questions. If you can even get 1 on 1 with your teacher, I think it would be easy for him or her to explain to you even if he or she is bad at teaching.

    Azarah is right in that for f(g(x)) you just plug in the g(x) equation into the values for x of f(x). I can't tell exactly what your questions are so here's an example:

    F(x)=x^2
    G(x) = x 3

    F(g(x))=(x 3)^2

    And a slightly more complicated problem:

    F(x)=3x 6 x^2
    G(x)=5x-4

    Now plug in (5x-4) for all x values in f(x).

    F(g(x))= 3(5x-4) 6 (5x-4)^2

    If the question was to find g(f(x)) then you plug in f(x) for all of the x values in g(x)

    G(f(x))=5(3x 6 x^2)-4

    This is confusing to understand initially but once you get the hang of it, it's quite simple :)

    I remember doing this 6 years ago and it is very useful to understand this.
     
  14. Ah forums has trolled me and all of my plus signs have been replaced with spaces  see if u can visualize lol