JAMB - Mathematics (1984 - No. 27)
If a = \(\frac{2x}{1 - x}\) and b = \(\frac{1 + x}{1 - x}\), then a2 - b2 in the simplest form is
\(\frac{3x + 1}{x - 1}\)
\(\frac{3x^2 - 1}{(x - 1)}\)2
x\(\frac{3x - 2}{1 - x}\)
\(\frac{3x^2 - 1}{(x - 1)}\)
Explanation
a2 - b2 = (\(\frac{2x}{1 - x}\))2 - (\(\frac{1 + x}{1 - x}\))2
= (\(\frac{2x}{1 - x} + \frac{1 + x}{1 - x}\))(\(\frac{2x}{1 - x} - \frac{1 + x}{1 - X}\))
= (\(\frac{3x + 1}{1 - x}\))(\(\frac{x - 1}{1 - x}\))
= \(\frac{3x + 1}{x - 1}\)
= (\(\frac{2x}{1 - x} + \frac{1 + x}{1 - x}\))(\(\frac{2x}{1 - x} - \frac{1 + x}{1 - X}\))
= (\(\frac{3x + 1}{1 - x}\))(\(\frac{x - 1}{1 - x}\))
= \(\frac{3x + 1}{x - 1}\)
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