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    • Thread Starter
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    These questions keep giving me problems even though, I should have cracked them by now. So, could someone explain to me the method to working them out? :puppyeyes:

    "The length of a rectangle is 3cm greater than its width. The area of the rectangle is 40cm². Find the length and width of the rectangle."

    Thank you for any replies.
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    if the width is x, what's the length in terms of x?

    what's the formula for area?
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    Let length = x

    Does this help:

    length * width = area

    x(x-3)=40
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    Why is it minus 3, shouldn't it be plus 3?
    I also don't understand why you multiply length by itself. :confused:
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    (Original post by 123mccann)
    Why is it minus 3, shouldn't it be plus 3?
    I also don't understand why you multiply length by itself. :confused:
    lenght = width + 3

    if length is x, then width + 3 = x so width = x - 3

    you multiply length by width to get area

    length = x

    width = x - 3

    area = x(x - 3)
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    (Original post by 123mccann)
    Why is it minus 3, shouldn't it be plus 3?
    I also don't understand why you multiply length by itself. :confused:
    It depends what you make x equal.

    If x is width, length is (x + 3) as it is 3cm longer than width.

    However, if you want x to be the length, the width is (x - 3), as the width is 3cm shorter than length.

    The area of rectangle is length x width. So you now have an expression for both length and width. Just multiply out x(x + 3) = 40; or x(x - 3) = 40.


    The x in the first sum is the width, the x in the second sum is the length.
    • Thread Starter
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    Oh right, thank you very much. I understand it now. I just find it difficult putting the question into an equation. :confused:
    I'm pretty sure it will baffle me again next time. :p:
 
 
 
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