Maths year 11

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    correct
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    (Original post by RDKGames)
    correct


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    Divide the shape in two rectangles, find their respective areas and add them together.
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    (Original post by RDKGames)
    Divide the shape in two rectangles, find their respective areas and add them together.
    Like this ?

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    (Original post by RDKGames)
    Divide the shape in two rectangles, find their respective areas and add them together.
    Like this ? .

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    (Original post by z_o_e)
    Like this ?

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    First equation is fine but if you're going by that then your second one is incorrect. Think about the line length 7x-2 in relation to the 2x at the top.
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    Split the diagram into 2 rectangles, and label all of the side lengths of each rectangle and it should become very clear.
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    (Original post by RDKGames)
    First equation is fine but if you're going by that then your second one is incorrect. Think about the line length 7x-2 in relation to the 2x at the top.
    Here


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    I think it's 5x-2

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    (Original post by z_o_e)
    I think it's 5x-2

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    The top length would indeed be 5x-2. Not sure why you multiplied (x+3) by itself there though.
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    (Original post by RDKGames)
    The top length would indeed be 5x-2. Not sure why you multiplied (x+3) by itself there though.
    How do I solve the last 2?


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    (Original post by z_o_e)
    How do I solve the last 2?


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    That's not quite right. I think you would find it easier to expand brackets using a table; do you know how?
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    (Original post by RDKGames)
    That's not quite right. I think you would find it easier to expand brackets using a table; do you know how?
    No?

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    Create a table like this. Since you are multiplying (x+3) by (5x-3), one goes on the top and the other goes on the side. The trick is that you separate the numbers by isolating them in their own squares; like 5x and -2 have different squares, likewise with x+3. Then fill it in by multiplying the corresponding column and row. For example, 5x2 is achieved from x multiplied by 5x . -2x is from -2 times by x.

    Once you fill them in, add them all up and you have your brackets expanded.

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    (Original post by RDKGames)
    Create a table like this. Since you are multiplying (x+3) by (5x-3), one goes on the top and the other goes on the side. The trick is that you separate the numbers by isolating them in their own squares; like 5x and -2 have different squares, likewise with x+3. Then fill it in by multiplying the corresponding column and row. For example, 5x2 is achieved from x multiplied by 5x . -2x is from -2 times by x.

    Once you fill them in, add them all up and you have your brackets expanded.

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    Thank you xx



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    (Original post by z_o_e)
    Thank you xx



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    Not quite. Top row is incorrect because x term on the 5 is SQUARED while the one on the -2 is NOT. Therefore you cannot take one away from the other like that.

    Second row, you are missing an x next to the 15.
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    (Original post by RDKGames)
    Not quite. Top row is incorrect because x term on the 5 is SQUARED while the one on the -2 is NOT. Therefore you cannot take one away from the other like that.

    Second row, you are missing an x next to the 15.
    Oh is it 3x cube?

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    (Original post by z_o_e)
    Oh is it 3x cube?

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    No it's simply 5x2-2x.

    It would be 3x2 if it was 5x2-2x2.
    It would be 3x3 if it was 5x3-2x3.
    They powers have to be the same in order to mix.
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    (Original post by B_9710)
    That's what I was asking for, the proof.
 
 
 
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