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Sophia.13

  • 3 years ago

Solve using two differemt methods. Explain which method you found to be more efficient. a. 3x-9y=3 6x - 3y= -24

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  1. wio
    • 3 years ago
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    The two methods are elimination and substitution.

  2. Sophia.13
    • 3 years ago
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    There is also graphing

  3. skullpatrol
    • 3 years ago
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    What have you tried?

  4. Sophia.13
    • 3 years ago
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    Nothing yet, i know how to do elimination. But i dont know how to substitution or graphing.

  5. skullpatrol
    • 3 years ago
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    Use elimination and find the answer first. All the methods should give the same answer, right?

  6. Sophia.13
    • 3 years ago
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    Ok

  7. skullpatrol
    • 3 years ago
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    $$ 3x-9y=3$$ $$ 6x - 3y= -24$$

  8. Sophia.13
    • 3 years ago
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    I got 3x-6y= -27 but i dont think its rigth is it?

  9. skullpatrol
    • 3 years ago
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    No.

  10. Sophia.13
    • 3 years ago
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    oh

  11. Sophia.13
    • 3 years ago
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    well, how do i do it?

  12. Azteck
    • 3 years ago
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    Do it simultaneously.

  13. skullpatrol
    • 3 years ago
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    You said you know how to use elimination. Try multiplying the first equation by $$-2$$ and add it to the second equation...

  14. skullpatrol
    • 3 years ago
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    $$ (3x-9y=3) (-2)$$ 6x - 3y= -24

  15. Azteck
    • 3 years ago
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    \[3x-9y=3 [1]\] \[6x - 3y= -24 [2]\] \[2\times [1]\] \[6x-18y=6 [3]\] \[[2]-[3]\] \[(6x - 3y) - (6x-18y)= (-24)-(6)\]

  16. Azteck
    • 3 years ago
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    \[-3y+18y=-30\] The x's cancel out. Now you can solve for y. Once you solve for y, you can then substitute the y component that you just found, into any one of the equations above to find your x-value.

  17. Azteck
    • 3 years ago
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    If you need further assistance, I will be happy to elaborate it in more simple terms.

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