## anonymous one year ago Functions f(x) and g(x) are described as follows: f(x) = −5x2 + 9 x g(x) 0 0 1 4 2 8 3 4 4 0 Which statement best compares the maximum value of the two functions? It is equal for both functions. It is 3 units higher for f(x) than g(x). It is 3 units lower for f(x) than g(x). It is 1 unit higher for f(x) than g(x).

1. freckles

Well have you found the max values of both functions?

2. freckles

f is already in vertex form

3. anonymous

no i havent.

4. freckles

$f(x)=a(x-h)^2+k \\ \text{ if } a \text{ is negative then } k \text{ is a \max} \\ \text{ if } a \text{ is positive then } k \text{ is a \min}$

5. freckles

And for g you just have to look for which g(x) value is the highest and that is the max

6. anonymous

I am very confused i am just learning this stuff.

7. freckles

compare the following two things: $f(x)=a(x-h)^2+k \\ f(x)-5(x-0)^2+9$ is there anyway you can determine what k is

8. freckles

everything is lined up where it should be a is -5 h is 0 k is...

9. anonymous

9?

10. freckles

yes

11. freckles

now followed what I said above

12. freckles

since a is negative then k is a max

13. freckles

you did have a is -5 so k=9 is your max

14. freckles

9 is the max value of f

15. freckles

can you look at your list of g(x) values and just say what the highest number is listed there

16. anonymous

8?

17. freckles

yes so the max of g is 8

18. freckles

are you able to answer the question now?

19. anonymous

20. freckles

so you think 9 is 3 units less than 8?

21. anonymous

OH

22. anonymous

Its D.

23. freckles

yes 9 is one more than 8

24. freckles

if you don't know the vertex form of a parabola you could graph the function given to you next time and just go to the peak of the mountain and find the highest y value there

25. anonymous

Can you help with 1 more?

26. freckles

I can try

27. anonymous

Mary wants to hang a mirror in her room. The mirror and frame must have an area of 7 square feet. The mirror is 2 feet wide and 3 feet long. Which quadratic equation can be used to determine the thickness of the frame, x? Square with an inner frame with height of 2ft on the left frame and width of 3ft on the top. Arrow on the bottom frame with an x and an arrow on the right frame with an x. x2 + 14x − 2 = 0 2x2 + 10x − 7 = 0 3x2 + 12x − 7 = 0 4x2 + 10x − 1 = 0

28. anonymous

let me get the graph

29. anonymous
30. freckles

|dw:1440176060259:dw|

31. freckles

ok so the area of that whole thing given is 7 ft^2

32. freckles

|dw:1440176151768:dw| what is the height of the rectangle?

33. freckles

I put black boxes around the numbers you might think interesting when answering that question

34. anonymous

35. freckles

Did you want to try to figure out the height of the rectangle?

36. freckles

Or did you want to guess at the choices of your question?

37. anonymous

38. freckles

I wasn't being rude. You were ignoring my question.

39. anonymous

I was not.

40. freckles

but you never answered my question...

41. anonymous

Its 2x^2

42. freckles

the total height is x+2+x or 2x+2 |dw:1440176571442:dw|

43. freckles

can you find the base length of the rectangle

44. freckles

|dw:1440176598630:dw|

45. anonymous

3x?

46. freckles

try again

47. freckles

|dw:1440176627302:dw|