Expanding and factorising quadratics

  • Always Two
    problem

    Always two

    Age
    14 to 18
    Challenge level
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    Find all the triples of numbers a, b, c such that each one of them plus the product of the other two is always 2.

  • Iff
    problem

    Iff

    Age
    14 to 18
    Challenge level
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    Take a triangular number, multiply it by 8 and add 1. What is special about your answer? Can you prove it?

  • Always Perfect
    problem

    Always perfect

    Age
    14 to 18
    Challenge level
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    Show that if you add 1 to the product of four consecutive numbers the answer is ALWAYS a perfect square.

  • Parabella
    problem

    Parabella

    Age
    16 to 18
    Challenge level
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    This is a beautiful result involving a parabola and parallels.

  • Unit interval
    problem

    Unit interval

    Age
    16 to 18
    Challenge level
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    Can you prove our inequality holds for all values of x and y between 0 and 1?

  • Powerful Factors
    problem

    Powerful factors

    Age
    16 to 18
    Challenge level
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    Use the fact that: x²-y² = (x-y)(x+y) and x³+y³ = (x+y) (x²-xy+y²) to find the highest power of 2 and the highest power of 3 which divide 5^{36}-1.
  • Spot the difference
    problem

    Spot the difference

    Age
    16 to 18
    Challenge level
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    If you plot these graphs they may look the same, but are they?
  • Polar Flower
    problem

    Polar flower

    Age
    16 to 18
    Challenge level
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    This polar equation is a quadratic. Plot the graph given by each factor to draw the flower.