## anonymous one year ago What statement correctly describes the key features of the graph of f(x) = 4(1/2)^x + 1 − 3?

1. anonymous

@phi

2. anonymous

Y-intercept of (0, −1), starts up on the left, gets closer to y = −3 on the right Y-intercept of (0, −1), starts down on the left, gets closer to y = −3 on the right Y-intercept of (0, 1), starts up on the left, gets closer to y = −3 on the right Y-intercept of (0, 1), starts down on the left, gets closer to y = −3 on the right

3. phi

is this $y = \left(\frac{1}{2}\right)^{x+1} -3$?

4. anonymous

you forgot the 4 in front of the 1/2

5. anonymous

other than that, you were right

6. phi

$y = 4\left(\frac{1}{2}\right)^{x+1} -3$

7. anonymous

yes! :)

8. phi

the y-intercept is the y value when x is 0 any idea what y is when x=0?

9. anonymous

1?

10. phi

you erase the x and put 0 in its place in the formula what do you get ?

11. anonymous

ok hold on:)

12. anonymous

0+1=1 right?

13. anonymous

-1! sorry

14. phi

the exponent x+1 becomes 0+1 or just 1 now do (1/2)^ 1 which is just 1/2 then do 1/2 * 4 - 3 or 2 - 3 or -1

15. phi

follow?

16. anonymous

yes okay so now we can elimate some answer choices and yes i do

17. phi

yes, it's A or B

18. phi

what do you get for x= -2 any idea?

19. anonymous

hold on:)

20. anonymous

-5?

21. phi

x+1 becomes -2 + 1 = -1 now do (1/2)^(-1) the negative exponent means you can "flip" the fraction and make the exponent positive so you get 2^1 or just 2 now do 4*2-3 = 8-3 = 5

22. anonymous

Oh! I get it :)

23. phi

at x=2, y=5 at x=0, y= -1 starts high on the left and gets smaller (asymptotes to -3)

24. phi

**x=-2 , y=5

25. anonymous

I see, I see

26. anonymous

so would it be B?

27. phi

yes, I think B. The language is not very clear. (whoever wrote it flunked basic English)

28. anonymous

hahah! I totally agree<3 :D