If (3y-9)^2+7=43, then what is(are the values of y?​

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If (3y-9)^2+7=43, then what is(are the values of y?​

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Thông Đạt 4 years 2021-09-05T00:33:31+00:00 2 Answers 115 views 0

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  1. Neala
    0
    2021-09-05T00:35:08+00:00
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    Answer:

    y=5

    Step-by-step explanation:

    (3y-9)(3y-9)=36

    apply a foil method

    9y^2-54y+81-36=0

    9y^2-54y+45=0

    quadratic formula

    y=5 / y=1

    substitute y=5 on the equation

    9(5)^2-54(5)+45=0

  2. giabao
    0
    2021-09-05T00:35:11+00:00
    Reply

    Answer:

    y = 1 and y = 5

    Step-by-step explanation:

    ( 3 y -9)^2 + 7 = 43\\\\((3y)^2 + (-9)^2 + 2(3y)(-9)) = 43 - 7\\\\(9y^2 + 81 -54y) = 36\\\\9y^2 -54y + 81 -36 = 0\\\\9y^2 -54y + 45 = 0\\\\9(y^2 -6y + 5) = 0\\\\y^2 - 6y + 5 = 0\\\\y^2 - 5y - y + 5 = 0\\\\y(y - 5) -1(y - 5 ) = 0 \\\\( y - 1 )( y - 5) = 0\\\\y = 1 \ , \ y = 5

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