Chap 6 Error Analysis Homework 2 Ex 6.2 Q1(f)

Go through the working and attempt to identify where the error is.

25 comments:

  1. This comment has been removed by the author.

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  2. He forgot that -4*-2x should be +8x, not -8x.

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  3. This comment has been removed by the author.

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  4. This comment has been removed by the author.

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  5. On Line 2, the third sign should be + and not -

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  6. he should change the negative signs to positive sign at -8x
    9x-3-20-8x=-10

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  7. There is a mistake at Line 2. -4*-2x = 8x not -8x!

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  8. The second line. It should be +8x as -4 x -2x is +8x

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  9. When a negative number is multiplied by another negative number, the answer will be a positive number. When negative 2x is multiplied by negative 4, the answer should be positive 8x and not negative 8x.

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  10. The sign on line 2 should be + and not -

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  11. In line two:it should be 20+8x as negative and negative equals positive.

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  12. The -8x on line 2 should be +8x as negative times negative is positive.

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  13. On the second line of this equation,it should be a positive sign instead of a negative one.As -4 times -2x,20-8x should be 20+8x.

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  14. the error is expanding from line 1 to 2, the error is -4(5-2x)=-20-8x. the correct way is -4(5-2x)=-20+8x

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  15. In line 2, it should be +8x , not -8x. Hence therefore, line 3 should be 17x - 23 = -10 . Line 4 should be 17x = 23 - 10 . Line 5 should be x = 13/17 .

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  16. Line 1: N/A
    Line 2: 20-8x should be 20+8x. When a negative sign and another negative sign is multiplied together, the product is a positive one.
    Line 3:N/A
    Line 4:N/A
    Line 5:N/A

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  17. The second line, He got muddled up. -4 x -2x is 8x as a negative times a negative is a positive.
    so 17x -23= -10
    17x=-10+23
    17x=33
    so x= 1 6/7

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  18. The second line should be 20+8x not 20-8x

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  19. The working should be as follows:
    3(3x-1) - 4(5-2x) = -10

    After Factorisation, the answer will be:
    9x-3-20+8x = -10

    Now we move all the common terams together.
    9x+8x-3-20 = -10
    9x+8x = -10+3+20
    17x = 13
    x = 17/13
    = 1/4/13

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  20. On Line 2, the '-' in 20 - 8x should be a '+'.
    So, it should be like this:
    Line 2: 9x -3 - 20 + 8x = -10
    Line 3: 17x -23 = -10
    Line 4: 17x = -10 + -23
    Line 5: x = -10 + -23/ 17

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    Replies
    1. Line 4: 17x = -33
      Line 5: x = -33/17

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