## anonymous one year ago For the graphed function f(x) = -(3)x - 1 + 3, calculate the average rate of change from x = 1 to x = 3. (5 points)

1. anonymous
2. anonymous

@dan815

3. anonymous

@nincompoop

4. jim_thompson5910

Fill in the blank: The point (1, _____) lies on that function curve.

5. anonymous

3? lol idk

6. jim_thompson5910

|dw:1436391895866:dw|

7. jim_thompson5910

|dw:1436391907246:dw|

8. jim_thompson5910

draw a vertical line through x = 1 |dw:1436391924628:dw|

9. jim_thompson5910

where does this vertical line cross the curve? |dw:1436391957168:dw|

10. anonymous

4? idk

11. jim_thompson5910

|dw:1436392018915:dw|

12. jim_thompson5910

how high is that point off the x axis (think of it as the ground)

13. anonymous

4...

14. jim_thompson5910

no, 2 actually

15. anonymous

wouldnt 2 be closer though

16. jim_thompson5910

|dw:1436392094265:dw|

17. anonymous

oh

18. jim_thompson5910

so you see how that point is (1,2) ?

19. anonymous

ohh wait i see in the screenshot

20. anonymous

yes

21. jim_thompson5910

what is the other point?

22. anonymous

2,0?

23. jim_thompson5910

(2,0) yes

24. jim_thompson5910

(1,2) and (2,0) are the two points

25. jim_thompson5910

use the slope formula $\Large m = \frac{y_{2}-y_{1}}{x_{2}-x_{1}}$ to find the slope

26. anonymous

so -2

27. jim_thompson5910

yes the slope of the line through those two points is -2

28. anonymous

29. jim_thompson5910

oh wait, it's x = 1 to x = 3 NOT x = 1 to x = 2

30. jim_thompson5910

there's one other point on the graph that has an x coordinate of 3 what is the y coordinate here?

31. anonymous

-6

32. jim_thompson5910

so the two points you'll use are (1,2) and (3,-6)

33. jim_thompson5910

use the same slope formula

34. anonymous

so-4

35. jim_thompson5910

good

36. anonymous

37. jim_thompson5910

sure

38. anonymous

Which logarithmic graph can be used to approximate the value of y in the equation 5y = 12? (5 points) http://gyazo.com/09247132268a7180076b6fd9c7b33364

39. jim_thompson5910

It says $\Large 5^y = 12$ right?

40. anonymous

yes sorry

41. jim_thompson5910

when you isolate y, what do you get

42. anonymous

how would i do that? like do i square root 5 i dont know lol

43. jim_thompson5910

what undoes exponents?

44. anonymous

square roots?

45. jim_thompson5910

logs do

46. anonymous

oh sorry

47. jim_thompson5910

if we solve for y, we get $\Large 5^y = 12$ $\Large y = \log_{5}(12)$ $\Large y = \frac{\log(12)}{\log(5)}$ $\Large y \approx 1.543959$

48. jim_thompson5910

So find the function where if you plug in x = 12, you'll get roughly y = 1.543959

49. anonymous

okay

50. anonymous

wait so if i graphed them would the answer show up as one of theoptions?

51. jim_thompson5910

look at your options which choice has (12, 1.543959) on it?

52. jim_thompson5910

obviously B and C are out because the y coordinates of the point with x coordinate 12 is negative

53. anonymous

d?

54. jim_thompson5910

why D?

55. anonymous

because it's 12,1.5

56. jim_thompson5910

what is the coordinates of that blue point for choice A?

57. anonymous

12,1

58. jim_thompson5910

good

59. jim_thompson5910

so that rules out A

60. anonymous

yay thanks!!

61. jim_thompson5910

np