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Complicated GCSE Maths Questions - Official Help Thread (All exam boards) Watch

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    Post difficult A/A* questions and we will all help each other get our heads around them.

    Two Questions for AQA (Specification 4360) - 19th June 2012, Unit 2
    Question 17
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    Question 18
    Here is an identity (3x + c)(x + c) ≡ 3x2 – dx + 16
    c and d are integers. Work out all possible pairs of values of c and d.
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    Question 18

    expand out brackets as normal....you will get 3x^2+3xc+cx+c^2=3x^2-dx+16

    x^2 terms of left hand side have to equal x^2 terms on right hand side....
    x terms on left hand side have to equal x terms on right hand side...
    number term(constant) on left hand side have to equal number terms on right hand side...


    3x^2=3x^2....x=3

    c^2=16......c=4 (squareroot)

    3c+c= -d.....sub in c to get........3(4)+4=-d..........12+4= -d......d=16
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    Hi guys,
    created these questions myself and are very challenging. These types of questions are usually found at the end of the paper and require logical thinking and problem solving skills. The document i've attached contains 3 questions, ordered from easiest to hardest. Give them ago and tell me how you found those questions. If you become stuck simply ask, and i can help you out.

    PS - the document is just named predicted questions because i was going to make predicted questions but then thought, leave it. So i just made random ones.

    THE SOLUTIONS WILL BE ADDED BY TOMORROW AS I AM CURRENTLY REVISING ADD MATHS.
    Attached Files
  1. File Type: docx Predicted Questions for Edexcel Paper 2.docx (42.0 KB, 98 views)
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    (Original post by chrisandmaddy)
    expand out brackets as normal....you will get 3x^2+3xc+cx+c^2=3x^2-dx+16

    x^2 terms of left hand side have to equal x^2 terms on right hand side....
    x terms on left hand side have to equal x terms on right hand side...
    number term(constant) on left hand side have to equal number terms on right hand side...


    3x^2=3x^2....x=3

    c^2=16......c=4 (squareroot)

    3c+c= -d.....sub in c to get........3(4)+4=-d..........12+4= -d......d=16
    LOOOL. He asked for possible answers, not the actual thing. P.S I think your wrong.
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    (Original post by gurpartapl)
    Hi guys,
    created these questions myself and are very challenging. These types of questions are usually found at the end of the paper and require logical thinking and problem solving skills. The document i've attached contains 3 questions, ordered from easiest to hardest. Give them ago and tell me how you found those questions. If you become stuck simply ask, and i can help you out.

    PS - the document is just named predicted questions because i was going to make predicted questions but then thought, leave it. So i just made random ones.

    THE SOLUTIONS WILL BE ADDED BY TOMORROW AS I AM CURRENTLY REVISING ADD MATHS.
    Just I need the answer to the first one.
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    oops sorry if got wrong end of stick!

    ps....im right!!!


    its called comparing coefficients!
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    Question 17:
    Line ABC is 2x + y = 6
    Hence y = -2x + 6
    y = mx+c, where c is y-intercept, hence y-intercept = 6. Therefore POINT B = (0,6)

    POINT A crosses the x-axis, hence its y value = 0
    Hence y = mx + c ----> 0 = -2x + 6 --> 2x = 6 ---.> x=3
    Hence POINT A = (3,0)

    A=(3,0), B=(0,6)=(3-3, 0+6)
    B is midpoint, so POINT C is (0-3, 6+6) = (-3, 6)

    POINT D is on the x-axis, so its y value = 0, therefore POINT D = (-7, 0) [and C = (-3, 6)].
    gradient = change in y/change in x = (yc - yd)/(xc - xd)
    m = (6-0)/(-3--7) = 6/4 = 3/2 or 1.5
    y = mx +c ----> y = 1.5x + c

    Then use: y-yd = m(x-xd) to find equation of line (where m=1.5, as previously established):
    y - 0 = 1.5x - 1.5*-7 = 1.5x + 10.5

    Hence y = 1.5x + 10.5
    or: 2y = 3x + 21
 
 
 
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