Anonymous
Anonymous asked in Science & MathematicsMathematics · 6 days ago

"The area of a rectangle is (x2-13x-30). If the width is (x+2),find the length." Can someone go through this step by step?

10 Answers

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  • sepia
    Lv 7
    4 days ago

    The area of a rectangle is (x^2 - 13x - 30). 

    If the width is (x + 2), the length is (x - 15).

  • 5 days ago

    area = length multiplied by width

    so length = area / width

    (x^2 -13x -30)/(x+2)= (x-15)(x+2)/(x+2) = x-15

    so length = x-15

  • 5 days ago

    The square root of a piece of pie 

  • Philip
    Lv 6
    5 days ago

    Every rectangle has a length, L and a width, W.;

    Every rectangle has an area, A where A = L*W...(1);

    Here we are given A = (x^2-13x-30) and W = (x+2).;

    By (1), L = A/W = (x^2-13x-30)/(x+2)...(2);

    We can factor A as (x+2)(x-15).;

    Then (2) becomes L = (x+2)(x-15)/(x+2)...(3);

    Clearly, for (x+2) =/= 0, (x+2) divides out in (3) giving L = (x-15).

     

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  • 6 days ago

    A = lw 

    x^2 - 13x - 30 = (x + 2)l

    x^2 - 13x - 30 = (x + 2)l

    .........x^2 - 13x - 30

    l = -------------------------

    ,,,,,,,,,,,,,x + 2

    ........(x -15)(x +2)

    l = ----------------------

    ..............x + 2

    l = x - 15 answer//

  • 6 days ago

     The area of a rectangle is (x^2 - 13x - 30). 

     If the width is (x + 2), the length is (x - 15)

  • Ian H
    Lv 7
    6 days ago

    The x + 2 factor cancels.

    The answer is x - 15.

    That is all.

  • nbsale
    Lv 6
    6 days ago

    First just factor the expression for the area:

    x^2 - 13x - 30 = (x+2)(x-15).

    So you divide that by x+2 and you get the length of x-15.

    You have no information that lets you solve for x, but you know it must be > 15 since the length must be positive.

    The question doesn't call for anything more than finding the expression for the length, x-15.

  • 6 days ago

     let length = ax + b

    ( ax + b ) ( x + 2 ) = x² - 13x - 30

    By inspection ( using the first term and the last term ), 

    ax² = x², thus a = 1

    2b = -30, thus b = -15

    length = x - 15

  • 6 days ago

    Use can use long division.

    .................x-15

    ......---------------

    x+2|x^2-13x-30

    .......x^2+2x

    .......----------

    .............-15x-30

    .............-15x-30

    .............----------

    ......................0

    The length is x - 15.

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