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Maths

Index notation

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Substitution

You might be asked to substitute a number into an expression.

For example , what is the value of 4p3 when p = 2?

We know that 4p3 means 4 × p × p × p, so when p = 2 we substitute this into the expression: 4 × 2 × 2 × 2 (or 4 × 23) = 32

Question

What is the value of 4y2 - y, when y = 3?

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Answer

33

Remember that (4 × y × y) - y, becomes (4 × 3 × 3) - 3 or 36 - 3.

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