## anonymous 4 years ago 2-5m=13 steps again...

1. Mertsj

Subtract 2 from both sides first.

2. Mertsj

What did you get?

3. anonymous

11

4. Mertsj

Now divide both sides by -5

5. Mertsj

What did you get?

6. anonymous

but that comes out to 2.2... and it needs to come out as a whole number..

7. Mertsj

That would be - 2.2 and it cannot come out as a whole number unless you copied the problem wrong.

8. anonymous

okay.. the real question is.. 13=5m-2 i didnt think it would natter if you flopped it around..

9. Mertsj

You didn't "flop it around". You changed 5m-2 to its opposite. That's like saying, ok, I'll just change this 10 to -10

10. anonymous

it still comes out 2.2...

11. Mertsj

12. Mertsj

$13+2=5m-2+2$

13. Mertsj

$15=5m$

14. Mertsj

Divide both sides by 5

15. anonymous

16. Mertsj

$\frac{15}{5}=\frac{5m}{5}$

17. Mertsj

yep

18. anonymous

okay tell me if i get this right to this next question.. -15=2t-11

19. anonymous

so would you add 15 to both sides?

20. Mertsj

ok

21. Mertsj

Remember you are trying to get the variable by itself. The variable has been multiplied by 2 and then had 11 subtracted from it. How would you "undo" those things so that the variable can be by itself?

22. anonymous

so.. then would you do -2t then? so then you could get rid of it?

23. Mertsj

You "undo" the stuff in reverse order. The variable was multiplied by 2 and 11 was subtracted. To undo that add 11 and then divide by 2

24. anonymous

oh.. i see that now. sorry.. this is really frustrating..

25. Mertsj

Well I know it is but if you keep at it, all of a sudden the light will come on.

26. anonymous

yeah, after i figure out what to either use to "undo" then i got the rest of the problem.. its just i never know what number to either subtract from or add.. you know what i mean?

27. Mertsj

I do know what you mean. Just always focus on getting the variable by itself by "undoing" the stuff. What did you get for this problem?

28. anonymous

i got, t=-2

29. Mertsj

that was very good. Do you have another one?

30. anonymous

yes i do, 7k-5=-19

31. Mertsj

Ok. What do you think comes first?

32. anonymous

and this is the part i mean i have troubles with.. like i never know if you would add -5bor -19..

33. Mertsj

What is the variable?

34. Mertsj

I don't mean the solution. I just want you to identify the variable. Is it x or y or ...what is it?

35. anonymous

the variable is k

36. Mertsj

Yes. Good. Now look at it. Is it multiplied or divided by something?

37. anonymous

7

38. Mertsj

Exactly. So at some point we're going to have to reverse that by dividing by 7.

39. Mertsj

But first, was anything added or subtracted to or from the k?

40. anonymous

yeah because the problem is 7k-5

41. Mertsj

Yes you are correct but I want you to tell me specifically what the number is and whether it was added or subtracted.

42. Mertsj

|dw:1328405964795:dw|

43. Mertsj

|dw:1328406078466:dw|

44. Mertsj

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45. anonymous

so for my question here 7k-5=-19 first i going to add -5 to -5 and -19 then rightt?

46. Mertsj

5 is subtracted because it says -5 so you should add 5 to both sides.

47. anonymous

okay

48. Mertsj

Let me draw it for you in a different way

49. Mertsj

|dw:1328406347372:dw|

50. Mertsj

Now divide both sides by 7

51. anonymous

so the answer all together then would be, k=-2

52. Mertsj

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53. Mertsj

Yes. Good. Do you have another one?

54. anonymous

yeah, 13=4x-11

55. Mertsj

What are you going to do first?

56. Mertsj

|dw:1328406584682:dw|

57. Mertsj

What first to get x alone?

58. anonymous

|dw:1328406584851:dw|

59. anonymous

this right??

60. Mertsj

Wow!1 You are very smart!!

61. anonymous

i just did it??! yay! lol. but.. im still not feeling very confident with it quite yet..

62. Mertsj

Do you have another one?

63. anonymous

okay, this one i have to draw out..

64. Mertsj

ok

65. anonymous

|dw:1328406824918:dw|

66. Mertsj

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67. anonymous

wait.. so like how would u figure that out.. like first step..

68. Mertsj

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69. anonymous

so then 3 would go under the 10-7

70. Mertsj

yep

71. Mertsj

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72. anonymous

then you would divide.. but what would u do to divide in this case?

73. Mertsj

We could divide by 1/2 but did anybody ever teach you that dividing is the same as multiplying by the reciprocal?

74. anonymous

ive heard that

75. Mertsj

So dividing by 1/2 is the same as multiplying by 2. It might be easier to just multiply by 2

76. Mertsj

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77. anonymous

oh, i kinda see this noww

78. Mertsj

Do you have another one?

79. anonymous

6+n/5=-4

80. Mertsj

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81. anonymous

so first would you subtract 6 to 6 and the -4?

82. Mertsj

Subtract 6 from both sides.

83. anonymous

-10

84. Mertsj

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85. anonymous

then what/

86. Mertsj

Well, we could divide by 1/5 or multiply by 5. Which do you choose?

87. anonymous

multiply

88. Mertsj

good choice.

89. anonymous

yeahh so then -10 *5?

90. Mertsj

yep

91. Mertsj

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92. anonymous

on my math homework now, i just finished 7 problems.. and before your help i couldn't even finish one.. THANKS!!!! :)

93. Mertsj

wonderful!! You keep at it sweetheart, and you'll be a star.

94. anonymous

lol now.. how would u figure this one? w+3w=20

95. Mertsj

Well now they threw us a curve ball, didn't they?

96. Mertsj

But this is easy. Just stay with me and answer by questions which may seem foolish.

97. anonymous

kk

98. Mertsj

What is 1 dog +3 dogs?

99. anonymous

4

100. Mertsj

4 what?

101. anonymous

dogs

102. Mertsj

What is 1 dollar + 3 dollars

103. anonymous

4 dollars

104. Mertsj

Now what if I said that I don't want to write out dollars all the time so I am just going to use d What would 1d + 3d be?

105. anonymous

4d

106. Mertsj

And supposing we would all agree that d means 1d then what would d+3d be?

107. anonymous

4d right?

108. Mertsj

right

109. Mertsj

so now in your problem you have w + 3w What do you suppose that is?

110. anonymous

4w

111. Mertsj

Exactly. So now your problem is 4w=20 How would you solve that?

112. anonymous

divide by 4 so 20 divided by 4 would be 5

113. Mertsj

Good. perfect!!

114. anonymous

so now theres this.. 3(y+5)=21

115. Mertsj

So have you heard of the distributive property?

116. anonymous

yeahh, we did it before.. but i forgot all about it.. but im sure ill remember once i see it again..

117. Mertsj

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118. Mertsj

Does that look familiar?

119. anonymous

idkk.. not really.. lol

120. Mertsj

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121. Mertsj

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122. anonymous

oooh yeahh!

123. Mertsj

you have to "distribute' the 3 to the y and to the 5

124. anonymous

so, 3y+15?

125. Mertsj

Great!!

126. anonymous

6a+7-a+-18

127. Mertsj

Did you get the other one?

128. anonymous

yes i got y=2

129. Mertsj

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130. Mertsj

That's what I got also.

131. anonymous

okayy cool

132. Mertsj

133. anonymous

soo would that be 5a+7=18?

134. Mertsj

Oh. There's an equal sign. Yes. 6a-a=5a

135. anonymous

okayy

136. anonymous

so a=-5?