Monday, 23 March 2015

Algebra (I): What's Wrong?

19 comments:

  1. The mistake was made in the 2nd working line, -5 x (-2y ) = 10y ( POSITIVE ), not negative.
    Also in the 3rd working line, it is 6x^2 not 6x. He/She forgot the exponent.
    Also, -2y + ( -10y ) = -2y-10y = -12y. But in the working statement he/she wrote -8y.

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  2. The mistake was made in the 2nd and 3rd line.
    2nd line: -5 times -2y equals to positive 10y, not negative.
    3rd line: It isn't needed

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  3. Mistake is in the 2 and 3 line the x2 disappeared in from the 3 line and the xy the x also disappeared.

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  4. The mistake made in the workings are:
    2nd line: 10y is positive, not negative as -5(-10y) will be positive (negative + negative =positive)
    3rd line: 6x should have the square (6x^2)

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  5. the first line has -5 x 3x and -5 times -2y so the second line is wrong because it should have been plus instead of minus. the third line is also wrong because it is simplified wrongly as 6x square cannot be simplified to 6x and 2xy cannot be simplified to 2y

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  6. For the second line, -5 x -2 = +10 , not -10 .
    For the third line, 6x square - 2xy cannot be simplified into 6x-2y

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  7. The mistake is on the second line.
    in second line,the (-5)x(-2)is 10y,because negative x negative is positive.

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  8. Second Line : -10y is the mistake. (-5*-2y=10y), because -*-=+.

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  9. In the second line, it should not be -10y but 10y (positive). It is because when -5 x -2y, the answer will be positive as it is two negatives multiplied by each other.

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  10. Mistake in 2nd and 3rd line
    2nd line: 10y should be positive not negative
    3rd line: exponent for 6x is missing. It should be 6x^2

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  11. The mistake is on the second line. Since negative times negative is positive, (-5) x (-2) is 10y, not -10y.

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  12. 2nd Line: It should be 15x+10x instead of 15x-10x.
    3rd Line: Unnecessary.

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  13. An error is in line 2 as -5*-2 is positive 10 not negative.Another error is the third line as the six lost its square when it shoudn't have.Thus the answer is wrong.

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  14. Negative 5 multiply by Negative 2y equals to Positive 10y instead of Negative 10y.
    It is not 6x but 6x^2
    The answer is 6x^2+2xy-15x-10y

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  15. For the second line, -5 x -2 =10(negative+negative=positive)
    For the third line, 6x^2 - 2xy cannot be simplified into 6x-2y. We can only subtract when there is like terms.(e.g.exponent,power)

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  16. missed out 6x^2 <- the power (line 3)

    -5y x (-2y) = 10y (line 2)

    it is 2xy not 2y (line 3)

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  17. -5y x (-2y)=10y(line 2), not -10y as negative times negative is positive
    should be 6x^2, missed out the ^2, 2x+10x=12x & the x from the 2xy(line 3)

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  18. The mistake is at the second line, where the -10y is suppose to be positive because negative x negative = positive.

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  19. Second line, negative x negative equals to positive, so -10y should be +10y.

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