Pearson Edexcel IAL Mathematics P1.1.1 Laws of indices

Practise using index laws to simplify powers, rewrite rational exponents and solve equations by matching common bases.

Exam points

rewrite expressions with a common base before equating indices to solve for constants
simplify products, quotients and powers with negative or rational indices

[Maximum number: 3]

In this question you must show all stages of your working.

Solutions relying on calculator technology are not acceptable.

By substituting $p=2^{x}$ , show that the equation

2 \times 4^{x}-2^{x+3}=17 \times 2^{x-1}-4

can be written in the form

4 p^{2}-33 p+8=0

With $p=2^x$ : $4^x=p^2,\ 2^{x+3}=8p,\ 2^{x-1}=\frac{p}{2}$ .

$2p^2-8p=\frac{17p}{2}-4$ $\Rightarrow4p^2-33p+8=0$

B1 M1 A1*

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