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math

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sovle: (3x - 2y)^2

The answer is 9x^2 + 4y^2 - 12xy but I do not know how to get the 12xy part.


20 - 4/5x is greater that or equal to 16, then:

The answer is x is less thatn or equal to 5 but again I do not know how to get this.

  • math - ,

    (3x - 2y)^2 = (3x-2y)(3x-2y)
    You could use FOIL
    (3x)(3x)+(3x)(-2y)+(-2y)(3x)+(-2y)(-2y)
    = 9x^2 -12xy +4y^2
    or use the distributive property of multipication directly
    3x(3x-2y) - 2y(3x-2y)
    =9 x^2 -6xy -6xy + 4y^2
    = 9x^2 - 12 xy + 4y^2

  • math - ,

    20 - 4/5x >/= 16
    If that is what you mean then

    100 x - 4 >/= 80 x
    20 x - 4 >/= 0
    20 x >/= 4
    x >/= 1/5
    or if you mean
    20 - (4/5)x >/= 16
    20 - 16 >/= (4/5) x
    4 >/= (4/5) x
    5 >/= x

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