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    (Original post by notnek)
    Now you just need to combine all the like terms. You can deal with surds similar to how you deal with letters in algebra so what's this:

    7x+6x-10x

    ?
    I got 3 root 2

    Thank you so much

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    Can someone please explain this

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    (Original post by z_o_e)
    Can someone please explain this

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    You've missed part of the question.
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    (Original post by notnek)
    You've missed part of the question.
    Oh sorry find values of P and Q

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    (Original post by z_o_e)
    Oh sorry find values of P and Q

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    Do you know how to find the turning point of a quadratic e.g. x^2+4x-5 ?

    Here you need to try and work backwards since you're given the turning point. Have a go at that and tell us if you get stuck. If you have no idea then that's fine, we can start you off.
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    (Original post by notnek)
    Do you know how to find the turning point of a quadratic e.g. x^2+4x-5 ?

    Here you need to try and work backwards since you're given the turning point. Have a go at that and tell us if you get stuck. If you have no idea then that's fine, we can start you off.
    I did this

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    (Original post by z_o_e)
    I did this

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    Assuming the question was to find the turning points of y=x^2-4x-5 then you completed the square correctly to get

    (x-2)^2-9

    But then this means the turning point is (2,-9) not (2, 9). You change the sign of the number in the brackets (-2 -> +2) and keep the sign of the other number (-9).


    Okay now imagine the question was the reverse i.e. you are told the turning point is (2,-9) and were asked to find the quadratic equation. You would work backwards to get

    y = (x-2)^2 - 9

    And then expand this to finish. Can you use this method for your question?
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    (Original post by notnek)
    Assuming the question was to find the turning points of y=x^2-4x-5 then you completed the square correctly to get

    (x-2)^2-9

    But then this means the turning point is (2,-9) not (2, 9). You change the sign of the number in the brackets (-2 -> +2) and keep the sign of the other number (-9).


    Okay now imagine the question was the reverse i.e. you are told the turning point is (2,-9) and were asked to find the quadratic equation. You would work backwards to get

    y = (x-2)^2 - 9

    And then expand this to finish. Can you use this method for your question?

    I got x^2 -4x +4
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    (Original post by z_o_e)
    I got x^2 -4x +4
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    Close but it's not quite right. Can you post your working?
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    (Original post by notnek)
    Close but it's not quite right. Can you post your working?


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    I'm not sure what you've done here. I'll start you off:

    The quadratic has a turning point at (2, 5). So if you work backwards the equation must be

    y=(x-2)^2+5

    If you expand then you'll get the answer.
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    Heya can someone help me on this plz
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    (Original post by z_o_e)
    Heya can someone help me on this plz

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    First consider the triangle \text{ADC} (one of the faces of the tetrahedron) and use Pythagoras' Theorem to work out the length DC which is the hypotenuse. The two side lengths for this triangle are given to you.

    Next consider the triangle ABD and again use Pythagoras to work out the length of the line DB as that is the hypotenuse.

    Then consider yet another triangle ABC and work out the length BC using Pythagoras once more.

    Finally, you should have all 3 sides of the triangle BDC. Apply the cosine rule and solve for angle BDC.

    N.B. The first 3 triangles are all right-angled, while the last one isn't so you cannot apply any SOHCAHTOA on that one.
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    (Original post by RDKGames)
    First consider the triangle \text{ADC} (one of the faces of the tetrahedron) and use Pythagoras' Theorem to work out the length DC which is the hypotenuse. The two side lengths for this triangle are given to you.

    Next consider the triangle ABD and again use Pythagoras to work out the length of the line DB as that is the hypotenuse.

    Then consider yet another triangle ABC and work out the length BC using Pythagoras once more.

    Finally, you should have all 3 sides of the triangle BDC. Apply the cosine rule and solve for angle BDC.

    N.B. The first 3 triangles are all right-angled, while the last one isn't so you cannot apply any SOHCAHTOA on that one.
    Thank you I have got the answer

    Any help on question B would be appreciated
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    (Original post by z_o_e)
    Thank you I have got the answer

    Any help on question B would be appreciated
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    The next step is to factorise each of those groups.

    So you can take a factor of 3x out of the first group and a factor of 14 out of the second group.
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    (Original post by z_o_e)
    Thank you I have got the answer

    Any help on question B would be appreciated



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    The area of the lawn would be (the total area of the lawn + path) - (area of the path)

    So, express area of the whole path in terms of x firstly, then use the above to work out what x is before finding the actual area of the lawn.
 
 
 
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