– The length of a rectangle is 2 less than 5 times its width. The area of the rectangle is 39 km². Find the length and width of the re

Question

– The length of a rectangle is 2 less than 5 times its width. The area of the rectangle is 39 km².
Find the length and width of the rectangle.

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Hưng Khoa 4 years 2021-07-21T16:55:56+00:00 1 Answers 20 views 0

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  1. MichaelMet
    0
    2021-07-21T16:57:07+00:00
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    Answer:

    Length is 13 and width is 3

    Step-by-step explanation:

    First find an equation that represents this situation.

    39 = w * (5w-2)

    This works because 39 (the total area) is w (the width) times 5w – 2 (the length). So solve for w.

    39 = w * (5w-2)

    First, distribute the w over the terms in parentheses

    39 = 5w^2 – 2w

    Then, subtract (5w^2 – 2w) from both sides.

    39 – 5w^2 – 2w = 0

    Factor the left side of the equation:

    (−5w−13)(w−3)=0

    Then set each factor equal to zero.

    −5w−13 = 0

    Add 13 to both sides, then divide both sides by -5 to isolate w. This leaves you with w = -13/5

    Then the other factor:

    w−3 = 0

    Add 3 to both sides. You’re left with w = 3.

    So w is either -13/5, or 3. And since the width can’t be negative, it is 3.

    Now to find the height, plug 3 into the equation we had from earlier:

    39 = w * (5w-2)

    Substitute w into the equation:

    39 = (3) * (5(3)-2)

    39 = 3 * (15 – 2)

    39 = 3 * (13)

    Because 3 * 13 is equal, 13 is the length.

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )