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# Make x the subject of the relation $$\frac{1 + ax}{1 - ax}$$ = $$\frac{p}{q}$$

### Question

Make x the subject of the relation $$\frac{1 + ax}{1 - ax}$$ = $$\frac{p}{q}$$

### Options

A) $$\frac{p + q}{a(p - q)}$$

B) $$\frac{p - q}{a(p + q)}$$

C) $$\frac{p - q}{apq}$$

D) $$\frac{pq}{a(p - q)}$$

The correct answer is B.

### Explanation:

$$\frac{1 + ax}{1 - ax}$$ = $$\frac{p}{q}$$ by cross multiplication,
q(1 + ax) = p(1 - ax)
q + qax = p - pax
qax + pax = p - q
∴ x = $$\frac{p - q}{a(p + q)}$$

## Dicussion (1)

• $$\frac{1 + ax}{1 - ax}$$ = $$\frac{p}{q}$$ by cross multiplication,
q(1 + ax) = p(1 - ax)
q + qax = p - pax
qax + pax = p - q
∴ x = $$\frac{p - q}{a(p + q)}$$

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