Simplify \(\frac{1}{5x + 5}\) + \(\frac{1}{7x+ 7}\)
 

  • A \(\frac{12}{35x + 1}\)
  • B \(\frac{1}{35(x + 1)}\)
  • C \(\frac{12x}{35(x + 7)}\)
  • D \(\frac{12}{35x + 35}\)
jamb 1986mathematics

The correct answer is D. \(\frac{12}{35x + 35}\)

\(\frac{1}{5x + 5}\) + \(\frac{1}{7x+ 7}\)

= \(\frac{7x + 7 + 5x + 5}{(5x + 5)(7x+ 7)}\)

= \(\frac{12x + 12}{35x^2 + 70x + 35}\)

= \(\frac{12(x + 1)}{35(x^2 + 2x + 1)}\)

= \(\frac{12}{35(x + 1)}\)

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