## chronicle 2 years ago │x – 5│ = 3 a. x = 8 and x = 2 b. x = 8 and x = –2 c. x = 8 d. x = 2

1. seidi.yamauti

if |x-5| >0 , then x-5=3 if |x-5| <0, then -x-(-5)=3; -x+5=3

2. seidi.yamauti

since x is a variable, you can't say |x-5| is > or < than 0, so you must consider both cases (unless the question tells you if it is < or >)

3. chronicle

d?

4. seidi.yamauti

not d

5. chronicle

ohh a?

6. seidi.yamauti

haha right. It's a

7. chronicle

8. seidi.yamauti

linear function means the graph will be a straight line so, if you take the same deltax for diferent x's, there should be the same deltay in both cases I guess it's a bit confuse - sorry I can't explain the right way cause my english is poor...

9. seidi.yamauti

like if you pick up x1=1, y1=1 & x2=2, y2=-3 for any other deltax = x2-x1 = 1, there should be the same deltay = y2=y1 = -4

10. chronicle

i suppose its not ?

11. seidi.yamauti

it is! plot the graph and you will see. Every point (x,y) is in an unique line

12. chronicle

oooh haha thanks

13. seidi.yamauti

|dw:1358481474606:dw|

14. chronicle

Tell whether the sequence is arithmetic. If it is, what is the common difference? –12, –7, –2, 3, . . . (1 point) yes; 5 yes; 8 yes; 3 no

15. seidi.yamauti

and you can even write the function, which is y=5-4x

16. chronicle

that one is yes; 5 ?

17. seidi.yamauti

right

18. chronicle

For the data in the table, does y vary directly with x? If it does, write an equation for the direct variation. x y 3 6 6 18 8 24 (1 point) yes; y = 2x yes; y = 3x yes; y = 4x no; y does not vary directly with x

19. chronicle

d?

20. seidi.yamauti

in this case, any member of the sequence is given by An= -12 + 5n

21. seidi.yamauti

hahaha, calm down!

22. chronicle

23. seidi.yamauti

well, that's the same as the other

24. seidi.yamauti

actually, it is yes

25. chronicle

The table shows the height of a tree as it grows. What equation in slope-intercept form gives the tree's height at any time? Time (months) Height (inches) 2 14 4 23 6 32 8 41 y = 9x + 2 y = 9/2x + 5 y = 9/2x y = 5x + 9/2

26. seidi.yamauti

(by the way, the previous one is d, sorry)

27. chronicle

i know, thank you

28. seidi.yamauti

you need to find the slope which is deltay/deltax

29. seidi.yamauti

y=ax+b a is the slope once you find it, just put any value for y from the tableand you get b

30. chronicle

Write y = –2/5x – 3 in standard form using integers. 2x + 5y = –15 2x + y = –3 2x + 5y = –3 x + y = –15

31. seidi.yamauti

it is (-2/5)x , right?

32. chronicle

yep

33. seidi.yamauti

just multiply everything by 5

34. chronicle

c?

35. chronicle

no a ! haha

36. seidi.yamauti

yes

37. chronicle

38. chronicle

Write the equation of a line that is perpendicular to the given line and that passes through the given point. y = –1/3x + 5; (4, 3) y = –3x + 15 y = 3x – 9 y = –4x + 3 y = –1/3x – 11

39. seidi.yamauti

you're welcome :)

40. seidi.yamauti

aaaaaa, I forgot the rule

41. seidi.yamauti

to be perpendicular, the multiplication of the slopes' values must be -1, is it right?

42. seidi.yamauti

the equation you need to find is y=ax+b a.(-1/3) = ? then substitute (4;3)

43. seidi.yamauti

ah, the slope2 of a perpendicular line is -1/slope1

44. seidi.yamauti

a1 the slope of a line a2 the slope of a perpendicular line then a2= -1/a1 or a1.a2=-1

45. chronicle

hmm C?

46. seidi.yamauti

yes

47. chronicle

What is the solution of the system? y = x – 14 y = –4x + 11 (5, –9) 1 over 5 and – (69 over 5) 5 over 3 and – (37 over 3) – (3 over 5) and – (73 over 5)

48. seidi.yamauti

subtracting the first by the second, you have 0=5x-25 this gives you x=5

49. seidi.yamauti

substitue x in any of the equations and you find y

50. chronicle

im confused

51. chronicle

idk where 0=5x-25 is from :/

52. seidi.yamauti

y=x-14 y=-4x+11 (minus) _____________ 0=x-(-4x)-14-11

53. seidi.yamauti

or since y=y, then x-14=-4x+11

54. chronicle

d?

55. seidi.yamauti

no, it's a, the simplest

56. chronicle

ohh lol

57. seidi.yamauti

haha

58. chronicle

Bradley and Ryan are having a contest to see who can collect the most bumper stickers. Bradley started with 23 bumper stickers and plans to add 4 each month. Ryan has 9 bumper stickers and plans to add 6 each month. After how many months will they have the same number of bumper stickers? (1 point) 10 months 2 months 7 months 51 months

59. seidi.yamauti

a way to solve it is writing the equations of stickers collected by each of them

60. seidi.yamauti

being m = months, then Bradley: Stickers=23+4m Ryan: Stickers=9+6m

61. seidi.yamauti

it means BRadley has 23 stickers and owns 4more each month and Ryan has 9 stickers and owns 6 more each month

62. chronicle

b.2 months?

63. seidi.yamauti

it is the same as the previous, and you can just write y=23+4x y=9+6x you want to know x

64. seidi.yamauti

not b

65. chronicle

hmm

66. seidi.yamauti

in this case, you don't want to know y

67. seidi.yamauti

either, you could substitute the options in the formulas and see if they give the same number

68. chronicle

i dont know :(

69. seidi.yamauti

Sure you know! Bradley: [number of stickers]=23+4x Ryan: [number of stickers]=9+6x

70. seidi.yamauti

if you call number of stickers as 'y' then you see that y MUST be the same in both equations

71. seidi.yamauti

and so the right hand sides of the equations

72. seidi.yamauti

so 23+4x=9+6x and you just need to find x

73. seidi.yamauti

the secret in this question is to transform words in equations, once you done that, you solve matematicaly (?)

74. chronicle

7months!

75. seidi.yamauti

yes! haha

76. chronicle

haha thank you thank you

77. seidi.yamauti

oh well, there's any other problem? I must go soon :P

78. chronicle

k last one How many solutions does the system have? 12y = –3x + 20 y = –1/4x + 5/3 (1 point) one two infinite none i think its infinite?

79. seidi.yamauti

let's see

80. seidi.yamauti

You are right

81. seidi.yamauti

but look at the system and you will see one is the same as the other

82. seidi.yamauti

one equation is the same as the other

83. seidi.yamauti

so you can't find just one value for (x,y) any x value gives an right y value

84. seidi.yamauti

multiply the second by 12, and you will end up with 2 equal equations

85. chronicle

oohh so its B?

86. seidi.yamauti

no, it is infinite, as you said

87. chronicle

i see

88. seidi.yamauti

you have 1 equation and 2 variables

89. seidi.yamauti

any given value of x will result in a y or any y will result in a x

90. seidi.yamauti

all of then right

91. chronicle

What is the slope of the line that passes through the pair of points? (5, 7), (2, 1) 8/7 2 –8/7 1/2

92. seidi.yamauti

deltay/deltax

93. chronicle

i still have to graph some questions but i will let you know

94. seidi.yamauti

if you are not in a hurry, i can answer as soon as i come back

95. chronicle

k im not in a hurry

96. seidi.yamauti

(7-1)/(2-5) or (1-7)/(5-2) You just need to use the correspondent positions to x's and y's values

97. seidi.yamauti

like (y2-y1)/(x2-x1) or (y1-y2)/(x1-x2) but not (y2-y1)/(x1-x2) or (y1-y2)/(x2-x1)

98. seidi.yamauti

any other question, message me :) bye!

99. chronicle

thank u