## anonymous one year ago Given the function f(x) = 4(x+3) – 5, solve for the inverse function when x = 3 –21 –16 –10 –1

1. anonymous

oh ok just plug it in and distribute

2. anonymous

got that?

3. anonymous

plug what in

4. anonymous

x

5. anonymous

i did but it didnt give me one of the answers

6. anonymous

|dw:1434112167391:dw|

7. anonymous

thats the first step

8. anonymous

okay then where do i go

9. anonymous

|dw:1434112336418:dw|

10. anonymous

thats the 2nd step

11. anonymous

hold on rewind did it wrong

12. anonymous

|dw:1434112506739:dw|

13. UsukiDoll

is that dividing by 0?!

14. anonymous

im sorry im having a bad day can you take over for me

15. UsukiDoll

I can try... the problem is asking for the inverse function when x = 3 meaning we need to find $f^{-1}(x)$ which is the inverse before we go further

16. UsukiDoll

first we can distribute and make this a bit easier f(x) = 4(x+3)-5 f(x) = 4x+12-5 f(x) = 4x+7

17. UsukiDoll

now f(x) =y y = 4x+7 we switch the x and y x=4y+7 and solve for y $x=4y+7$ $x-7 = 4y$ $\frac{x}{4}-\frac{7}{4} = y$

18. UsukiDoll

now we are given that x = 3 so we plug it in $\frac{3}{4} -\frac{7}{4} = y$

19. UsukiDoll

we can subtract the numerator since we have 4 as the same denominator

20. UsukiDoll

$\frac{-4}{4} = y$ $-1=y$

21. anonymous

thank you