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anonymous

  • one year ago

Can someone help me solve this expression: 15-20×-5+–1=

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  1. anonymous
    • one year ago
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    Hey again :D one sec.

  2. ccswims
    • one year ago
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    remember PEMDAS

  3. anonymous
    • one year ago
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    Uh -9-20x, but if you are distributing then -9=20x = -2.222222222

  4. ccswims
    • one year ago
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    OH WAIT. lol i thought that "x" was a multiply symbol XD

  5. mathstudent55
    • one year ago
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    Is this the expression? \(\Large 15 - 20 \times (-5) + (–1) = \)

  6. anonymous
    • one year ago
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    Yeah

  7. anonymous
    • one year ago
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    here is the math :P 15-20x-5+-1 15-5+-1=-9 -9-20x= +20x to both sides = -9=20x simple division leads us to -2.222222

  8. anonymous
    • one year ago
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    Wait no there aren't any parenthesis

  9. mathstudent55
    • one year ago
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    You must follow the correct order of operations. Multiplications and divisions come before additions and subtractions.

  10. anonymous
    • one year ago
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    simple isolation of the variable right ?

  11. anonymous
    • one year ago
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    Yeah @Etrainx

  12. calculusxy
    • one year ago
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    \[15 - 20 \times (-5) + (-1)\] \[15 + 100 + (-1)\] \[115 + (-1)\] \[114\]

  13. anonymous
    • one year ago
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    Should I multiply -20×-5 since its multiplication & following the order of pemdas ?

  14. anonymous
    • one year ago
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    OH i see

  15. anonymous
    • one year ago
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    you have 20 * (-5)

  16. anonymous
    • one year ago
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    i have 20x

  17. anonymous
    • one year ago
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    But the 20 is negative

  18. calculusxy
    • one year ago
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    The x really means multiplying. You're not working with variables, I believe.

  19. calculusxy
    • one year ago
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    @Halia You're correct. It's -20 because of the minus sign.

  20. anonymous
    • one year ago
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    when you subtract a negative number it becomes positive though.

  21. anonymous
    • one year ago
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    Yeah @calculusxy

  22. calculusxy
    • one year ago
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    @Etrainx You need to work with PEMDAS and this states that multiplying is before subtracting. Thus, you need to do -20 times -5.

  23. anonymous
    • one year ago
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    Wait so I multiped -20×-5 and I got +100

  24. anonymous
    • one year ago
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    I think these mathletes have it from here :P

  25. calculusxy
    • one year ago
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    Yes that's correct .

  26. mathstudent55
    • one year ago
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    That means you must start with \(20 \times (-5)\) \(\Large 15 - \color{red}{20 \times (-5)} + (–1) =\) \(\Large = 15 - \color{red}{(-100)} + (–1) \) Now we only have additions an subtractions, so we do them in the order they appear from left to right: \(\Large =15 - (-100) + (–1) \) \(\Large =15 + 100 -1 \) \(\Large =115 - 1\) \(\Large =114\)

  27. calculusxy
    • one year ago
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    The work that I did but explained in a better way @mathstudent55

  28. calculusxy
    • one year ago
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    ;)

  29. calculusxy
    • one year ago
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    It's confusing, but just remember to take into consideration the sign (plus or minus) because that determines whether the following integer will be negative or positive.

  30. anonymous
    • one year ago
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    Mkay I understand it now :) thanks guys I really appreciate it !!!

  31. calculusxy
    • one year ago
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    You're very welcome @Halia :)

  32. mathstudent55
    • one year ago
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    Order of operations PEMDAS P - first do what is inside parentheses E - then do exponents MD - then do multiplications and divisions from left to right in the order they appear AS - finally do additions and subtractions in the order they appear from left to right

  33. mathstudent55
    • one year ago
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    You're welcome.

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