JAMB - Mathematics (1981 - No. 21)

Solve \(\frac{1}{x + 1}\) - \(\frac{1}{x + 3}\) = \(\frac{1}{4}\)
x = -1 or 3
x = 1 or 3
x = 1 or -5
x = -1 or 5
x = -1 or -3

Explanation

\(\frac{1}{x + 1}\) - \(\frac{1}{x + 3}\) = \(\frac{1}{4}\)

\(\frac{x + 3 - x - 1}{(x + 1)(x + 3)}\) = \(\frac{1}{4}\)

\(\frac{2}{x^2 + 4x + 3}\) = \(\frac{1}{4}\)

= x2 + 4x + 3 = 8

x2 + 4x - 5 = 0

= (x - 1)(x + 5) = 0

x = 1 or -5

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