## MaeganR 2 years ago Point-Slope Form: "Graph each equation."

1. MaeganR

#5. y-2=2(x+3) #6. y+3=-2(x+1) #7. y+1=-3/5(x+5)

2. DHASHNI

|dw:1358042338363:dw|

3. MaeganR

How do you show your work?

4. DHASHNI

5. MaeganR

:O

6. DHASHNI

buts its k i'll tell u how to plot

7. MaeganR

yeah i need to show my work too

8. DHASHNI

for the given equation u got to make up a table for getting the points

9. MaeganR

huh.?

10. MaeganR

?

11. DHASHNI

for the given equation u got to make up a table for getting the points when u put x=0 in the given equation y value becomes 8 so , (0,8) is one of the points in the given straight line when u put y=0 in the given equation x value becomes 3 so, (3,0 ) is also one of the points in the given straight line|dw:1358043164412:dw|

12. DHASHNI

|dw:1358043209533:dw|

13. DHASHNI

and for the rest equation do the same u'll easily get plotted!

14. MaeganR

what the. im forever stupid. i hate math.

15. DHASHNI

huh.?

16. MaeganR

im so confused.

17. Azteck

#5. $y=2x+8$ #6. $y=-2x-5$ #7.$y=-\frac{ 3 }{ 5 }-4$ |dw:1358111862798:dw| |dw:1358111959201:dw|

18. Azteck

The #7 had a mistype. $y=-\frac{ 3 }{ 5 }x-4$ forgot the x.

19. MaeganR

How do you do that?

20. Azteck

Make sure when you draw the graphs, include the corresponding equation next to the line.

21. Azteck

Okay, please specify. Are you stuck with getting the equations into intercept form or are you stuck with the sketching onto the graph?

22. Azteck

Just to let you know I purposely haven't done #7 just to see where your mind is at. So if you're stuck with sketching we can go through #7 together as an example to make sure you understand.

23. Azteck

purposely didn't do*

24. MaeganR

#5 this is what I got when I did it: y -2= 2(x+3) 1 - 2 +2(1+3) 1-2=2(4) 1-2=8 (-8,-1)

25. MaeganR

1-2=2(1+3) Ooops.^

26. Azteck

okay, don't do that. That's a very slow way of sketching them. I got used to a method, where once you learn it completely, you can sketch the equation straight away in 10 seconds after looking at the equation.

27. MaeganR

how do you do that? and btw: is that correct anyways?

28. MaeganR

?

29. Azteck

Okay, do you know how to put the equations in to point intercept form?

30. Azteck

y=mx+b where m is the gradient of the line, b is a constant.

31. MaeganR

y=mx+b is the formula, but i dont know how to do anything

32. Azteck

Okay, good.

33. Azteck

Do you know how to expand?

34. MaeganR

m is the slope ik that

35. MaeganR

what is expanding?

36. Azteck

Ah, okay. Now that is something your teacher should have taught you before all this sketching and stuff.

37. MaeganR

my teacher just teaches everything in the book. in fact, we dont even use books. she just teaches us on the board and thats how we "LEARN".

38. Azteck

#5. y-2=2(x+3) Expand this part: $2(x+3)$

39. Azteck

Don't you know how to remove the brackets?

40. MaeganR

is it also called distribute?

41. MaeganR

what is a bracket?

42. MaeganR

[]?

43. Azteck

I think so. Because I'm probably not from your country where you might teach differently. I meant paranthesis. I just call it brackets because it's maths and maths teachers don't care about the technical terms of that stuff.

44. Azteck

Okay, If you expand/distribute $2(x+3)$ Wouldn't you get $2(x)+2(3)$

45. Azteck

and then you get $2x+6$

46. MaeganR

yesh brb

47. MaeganR

ok so hi

48. MaeganR

#5. y-2=2(x+3) How do we do this?

49. Azteck

okay now, you have y-2=2x+6

50. MaeganR

yes

51. Azteck

you want to put that into y=mx+b. Wouldn't you have to move the -2 to the LHS(Left Hand Side)?

52. MaeganR

wait how do you get the y+3 to be y-2?

53. Azteck

what? where's that?

54. Azteck

You're looking at the second one. I'm at the first one.

55. MaeganR

nvm. sorrry i was looking at two different problems.

56. MaeganR

yeah lol

57. Azteck

Okay, so put $y-2=2x+6$ into this form y=mx+b

58. MaeganR

is 2 m or is 6 m? 2?

59. MaeganR

because 6 would be b right?

60. Azteck

You're confusing me and we haven't started doing the other parts yet. Look at $y−2=2x+6$

61. Azteck

Now tell me what's the difference between this when you disregard the m's and b's in this equation: $y=mx+b$

62. MaeganR

y=x?

63. Azteck

Okay. Have you played a game called Spot The Difference? You're trying to find the difference between that equation and the first one.

64. Azteck

Come'on, this is the easiest form of mathematics at a standard level. You must know this in order to continue.

65. Azteck

Okay, here's something you should know. Collect the like terms.

66. Azteck

Do you know what collecting like terms is? Or have you not paid attention in class for a few years?

67. MaeganR

Ok. This is what ive done if it helps any.

68. MaeganR

and its backwards.

69. Azteck

That's going to be hard to read don't you think. Okay, I'm asking you this sole question.

70. MaeganR

The teacher I have does not explain, she only gives us frayer diagrams to follow. This is why this is so confusing to me.

71. Azteck

Do you understand the statement: "Collecting like terms"

72. MaeganR

yeah

73. MaeganR

is y=2x+8 anything to do with the answer?

74. Azteck

Yes!! Great work!!!

75. Azteck

Now, this is the easy part. That's what I think.

76. MaeganR

so now what do i do to get it to be point-slope form?

77. Azteck

All you have to do when sketching is find the x and y intercepts!

78. Azteck

That is point-slope form?

79. MaeganR

ok so i can plug in like (1,1) and (3,3)?

80. Azteck

No!!!

81. MaeganR

y=2x+8 is slope-intercept form. I need it to be point-slope form which is y-y1=m(x-x1). Wait.. I think i know how to do that..

82. Azteck

Always when sketching lines, you start off by making x=0

83. Azteck

so that means, you substitute x with 0!

84. Azteck

y=2(0)+ 8

85. Azteck

Anything multiplied by 0 always gives you zero!!

86. Azteck

Now you found that when you substitute x with 0 you get y=8

87. Azteck

And your coordinates would be (0, 8). Because coordinates always look like this: (x, y)

88. MaeganR

i get it. y=2x+8 y=2(0)+8 y=0+8 y=8 !!! :D

89. Azteck

Yes!! Now that's called finding the y-intercept. What would you do to find the x-intercept? How would you eliminate y in order to find x?

90. MaeganR

whoa. whoa. whoa. hold up. let me think...

91. MaeganR

you would plug in 0 for y?

92. Azteck

WELL DONE! awesome job @MaeganR!

93. Azteck

So what would you get for x?

94. Azteck

when you plug in 0 into y?

95. MaeganR

let me solve it..

96. MaeganR

0=2x+8 is how you start right.?

97. Azteck

Yes.

98. MaeganR

-4=x !?!?!?!

99. Azteck

Yes!!!Correct!!

100. MaeganR

so it would be (-4,8) but how do you go up or down.?

101. Azteck

so now what would the co-ordinates of the x-intercept be? Remember the coordinates take in the shape of this: (x-value, y-value)

102. Azteck

Yes!

103. MaeganR

wait. slope=2 2/1 up 2 over 1?

104. Azteck

No!! Don't do that.

105. Azteck

Forget the slope when sketching.

106. MaeganR

but htats what my teacher says to do? ):

107. Azteck

Haha, when you go up to senior years, all you do is put important features when sketching. The sketch doesn't need to be 00% perfect and to scale.

108. Azteck

100%

109. MaeganR

110. MaeganR

oh. oh. oh. I get it.

111. Azteck

Then if you're in 7th grade advanced, you should be smart as hell. Taking a 9th grade class when you're in 7th grade would require some form of intelligence and dexterity at mathematics. You should know allt his because this is 7th grade maths.

112. MaeganR

so (-4,0) and (0,-8)!?!?!?!?!

113. Azteck

Yes.

114. Azteck

Now run run a line along the two points

115. Azteck

You don't need to be precise in your placement of the coordinates.

116. Azteck

but make sure the x and y intecept are on the x and y axis respectively.

117. MaeganR

118. Azteck

Why are you skipping grades with this limited knowledge of maths? If you keep going at this rate, you're on the road to failure.

119. Azteck

That's my 2 cents.

120. MaeganR

yay. thank you so much. ive been so frustrated for a month because nobody would actually take the time to explain the whole thing to me in unbig scarey words. thank you so much. :)

121. Azteck

No worries. I think keeping it simple and just using baby talk always makes more sense than sophisticated and complicated words.

122. MaeganR

because i have to do this. theres no way out of the advanced program. once the school puts you in it without youre choice youre there, whether you fail or not.

123. MaeganR

yeah. always^.

124. MaeganR

im going to close the question now, but you can message me(: