## anonymous one year ago f(x)=4x+3 helpp

1. whovianchick

What are we helping to do?

2. anonymous

figure out f(x)=4x+3

3. anonymous

can you walk me through it

4. whovianchick

What do you mean figure it out? What are the instructions on the problem?

5. anonymous

how do you do it

6. anonymous

f(x) = 4x + 3 is a statement, not a question. What are you trying to do with the function?

7. anonymous

get like an answer at the end what would i tell my teacher

8. anonymous

what were you asked? there has to be some instructions

9. anonymous

evaluate it

10. Vocaloid

did they give you any other information?

11. Vocaloid

like, did they give you an x value?

12. anonymous

ok, now we're getting somewhere. Are you supposed to evaluate it at a specific value of x?

13. anonymous

lets say x is 2

14. anonymous

ok, so you would substitute 2 for x f(x) = 4x + 3 f(2) = 4(2) + 3 then simplify that

15. whovianchick

Don't multiply f and 2 though, that's basically y. It stays f(2), or function of 2.

16. anonymous

ok

17. anonymous

11

18. anonymous

yep

19. anonymous

can i ask a couple more

20. anonymous

ok

21. anonymous

f(x)=2x+4 G(x)=X+1

22. anonymous

no actually

23. anonymous

f(x)=5x+3 G(x)=x+4

24. anonymous

ok what are the instructions for this one?

25. anonymous

i have to combine them but I'm confused

26. anonymous

ok, there are lots of different ways to combine functions. It really depends on what you're asked for. Do you have a specific combination, or do you just want me to show you some

27. anonymous

can you show me some

28. anonymous

ok let's start with the basic 4 Adding $$f(x) + g(x) = 5x + 3 + x + 4$$ $$= 6x + 7$$ Subtracting $$f(x) - g(x) = 5x + 3 - (x + 4)$$ $$=5x+3-x-4$$ $$=4x-1$$ $$g(x) - f(x) = x + 4-(5x+3)$$ $$=x+4-5x-3$$ =$$-4x+1$$ Multiplying $$f(x)\cdot g(x)=(5x+3)(x+4)$$ $$=5x^2+20x+3x+12$$ $$=5x^2+23x+12$$ Dividing $\frac{ f(x) }{ g(x) }=\frac{ 5x+3 }{ x+4 }$ $\frac{ g(x) }{ f(x) }=\frac{ x+4 }{ 5x+3 }$

29. anonymous

Then you can get more complex with something like $$2f(x)-3g(x)=2(5x+3)-3(x+4)$$ =$$10x+6-3x-12$$ =$$7x-6$$

30. anonymous

You can also compose functions, which is basically putting one inside the other. To find f(g(x)) replace the x in f(x) with the function from g(x). $$f(g(x))=5(x+4)+3$$ $$=5x+20+3$$ $$=5x+23$$ To find g(f(x)), do the opposite and replace the x in g(x) with f(x) $$g(f(x))=(5x+3)+4$$ $$=5x+7$$

31. anonymous

ok can you walk me through on Subtracting f(x)−g(x)=5x+3−(x+4) =5x+3−x−4 =4x−1 g(x)−f(x)=x+4−(5x+3) =x+4−5x−3 =−4x+1 how'd you get that

32. anonymous

from the first line to the second you have to distribute. -(x + 4) = -x - 4 for the first one and -(5x + 3) = -5x - 3 then you combine like terms Is that what you meant?

33. anonymous

yea thank you and what about the others sorry I'm asking so much its just that i need to pass this

34. anonymous

no problem. for multiplying you usually have to use FOIL or do some distribution. dividing is just writing one on top of the other like a fraction

35. anonymous

ok

36. anonymous

Most of this is really knowing how to apply the distributive property and combine like terms

37. anonymous

ok thank you

38. anonymous

you're welcome