Expanding and factorising quadratics

There are 38 NRICH Mathematical resources connected to 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.
2-Digit Square
problem

2-Digit Square

Age
14 to 16
Challenge level
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A 2-Digit number is squared. When this 2-digit number is reversed and squared, the difference between the squares is also a square. What is the 2-digit number?
Novemberish
problem

Novemberish

Age
14 to 16
Challenge level
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a) A four digit number (in base 10) aabb is a perfect square. Discuss ways of systematically finding this number. (b) Prove that 11^{10}-1 is divisible by 100.
Common Divisor
problem

Common Divisor

Age
14 to 16
Challenge level
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Find the largest integer which divides every member of the following sequence: 1^5-1, 2^5-2, 3^5-3, ... n^5-n.
Code to Zero
problem

Code to Zero

Age
16 to 18
Challenge level
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Find all 3 digit numbers such that by adding the first digit, the square of the second and the cube of the third you get the original number, for example 1 + 3^2 + 5^3 = 135.
Two Cubes
problem

Two Cubes

Age
14 to 16
Challenge level
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Two cubes, each with integral side lengths, have a combined volume equal to the total of the lengths of their edges. How big are the cubes? [If you find a result by 'trial and error' you'll need to prove you have found all possible solutions.]
Telescoping Functions
article

Telescoping Functions

Take a complicated fraction with the product of five quartics top and bottom and reduce this to a whole number. This is a numerical example involving some clever algebra.
Mega Quadratic Equations
problem

Mega Quadratic Equations

Age
14 to 18
Challenge level
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What do you get when you raise a quadratic to the power of a quadratic?