What's Wrong? Q10 (Type 2)

Describe what's wrong with the working and/or answer.
Suggest how it should look like.


9 comments:

  1. The answer is suppose to be (3x-8y)^2

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  2. (3x)^2 - 2(24xy) + (8y)^2 ≠ (3x+8y)^2
    = (3x-8y)^2


    Owen and shawn kit btwfyi.

    ReplyDelete
  3. in this situation, it should be (a-b)^2.
    as a is 3x and b is 8y, it should be (3x-8y)^2 instead of (3x+8y)^2

    ReplyDelete
  4. Whats wrong: operation error
    How it should look like: = (3x-8y)^2

    Sandy and Ruoyu

    ReplyDelete
  5. Mavis & Qianhui8/17/2011 08:17:00 AM

    This is a type 2 question and it should be in a (a-b)^2 format and not in a (a+b)^2 format .
    The sign in the final answer should be '-'
    Final answer : (3x-8y)^2

    ReplyDelete
  6. M4®k †å¥ & Yi De8/17/2011 08:18:00 AM

    This is a type 2 question, therefore the answer should be in (a-b)^2 format. So the answer should be (3x - 8y)^2, not (3x + 8y)^2.

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  7. Yi Chieh,Kai En, Jiajun

    The answer should be (3x-8y)^2 because it follows the pattern of (a-b)^2.

    ReplyDelete
  8. Matthew and Wei Siew8/17/2011 08:20:00 AM

    This student's working is correct, however his/her answer is wrong. The answer should be "(3x - 8y)^2" and not "(3x + 8y)^2" as the formula is (a-b)^2 = a^2 = 2ab + b^2

    The answer should be ->
    9x^2 - 48xy + 64y^2
    = (3x)^2 - 2(24xy) + (8y)^2
    = (3x - 8y)^2

    ReplyDelete