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Is these algebraic expression correct

  1. Jul 30, 2009 #1
    1.(x - 3)2 = 4
    x2 - 6x + 5 = 0
    (x - 1)(x - 5) = 0
    x = -1, -5
    (is this correct)

    2. 2x + 4 / x +1 = x - 8 / 2x - 1
    (2x + 4)(2x - 1) = (x - 8)(x + 1
    4x2 - 2x + 8x - 4 = x2 - 7x -8
    4x2 - 6x - 4 = x2 - 7x - 8
    (where do i go from here)

    3. (x / 3) - (y / 2) = -1
    (y / 2) = -4 - 3x
    6x + y = -8
    y = -8 - 6x
    (x / 3) - (-4 - 3x) = -1
    (10 / 3) x + 4 = -1
    x = -5 / (10 / 3) = (-3 / 2) x = -3 / 2
    6(-3 / 2) + y = -8
    y = -8 + 6(-3 / 2)
    y = -8 + (-18 / 2)
    y = (-144 +- 16 / 16) y = -10
    (is this correct)
     
  2. jcsd
  3. Jul 30, 2009 #2

    Pengwuino

    User Avatar
    Gold Member

    1. No, they should be positive. If you plugged in either x=-1 or x=-5, you'd see that product didn't equal 0.

    2. For this question, is what you're asking [tex]\frac{{2x + 4}}{{x + 1}} = \frac{{x - 8}}{{2x - 1}}[/tex]? If so, it looks good. Now you simply want to subtract [tex]x^2 - 7x - 8[/tex] from both sides so you have 0 on the right side and a simple quadratic on the left.

    3. This looks a little confusing. Can you put spaces between each set of equations so we know exactly what you're doing? If the third line is suppose to be manipulation of the first line, it doesn't look correct.
     
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