## coolaidd 2 years ago ..

1. ParthKohli

Just subtract for finding (f - g) and add for finding (f + g).

2. tjones89

(f-g)(x) = f(x) - g(x)

3. ParthKohli

$\rm (f - g)(x) = (2x - 2)-(x + 4)$$\rm (f + g)(x) = (2x + 2) + (x + 4)$

4. ParthKohli

Oh, then it gets a little difficult... you have to plug g(x) into f(x).

5. ParthKohli

For example, if you got $$\rm f(x) = x^2$$ and $$\rm g(x) = x+1$$, then$\rm f(g(x)) = f(x + 1) = (x + 1)^2$

6. coolaidd

oh..ok :/

7. coolaidd

soo what would this be?

8. bluebrandon

for f(g(x)) just replace all the x in 2x-2 with (x+4) and for g(f(x)) just replace all the x in x+4 with (2x-2)

9. jiteshmeghwal9

$$x(f-g)$$=$$f(x)-g(x)$$ now put the values of $$f(x)$$ & $$g(x)$$ & solve them.

10. nubeer

yup.. thats how its done.

11. coolaidd

thanks!

12. nubeer

welcome.

13. coolaidd

so would it then be 2x+8-2 8x-8?

14. nubeer

how u got 8x-8?

15. coolaidd

2x times +4 and-2 times +4

16. nubeer

noooo... (2x-2) +4 u have to just open the bracket.. if there is a positive or negative sign outside the bracket that means its addint or subtracting not multiplying. your expression will be like 2x-2 +4

17. coolaidd

so it would just be 2x-2 +4? i dont have to solve it?

18. nubeer

(2x-2)4 if it was written liek this then u had to multiplied.. and yes that would be your answer just simplify it 2x+2 would be your answer for gf(x)

19. coolaidd

thanks!

20. nubeer

welcome ..