Question

Find (a + b) ÷ (a – b) if a = ${\displaystyle \frac{-3}{5}}$, b = ${\displaystyle \frac{2}{15}}$

Answer 1

a = ${\displaystyle \frac{-3}{5}}$, b = ${\displaystyle \frac{2}{15}}$

a + b = ${\displaystyle \frac{-3}{5}+\frac{2}{15}}$

= ${\displaystyle \frac{-3\times 3+2}{15}}$

= ${\displaystyle \frac{-9+2}{15}}$

= ${\displaystyle \frac{-7}{15}}$

a − b = ${\displaystyle \frac{-3}{5}-\frac{2}{15}}$

= ${\displaystyle \frac{-3\times 3-2}{15}}$

= ${\displaystyle \frac{-9-2}{15}}$

= ${\displaystyle \frac{-11}{15}}$

(a + b) ÷ (a – b) = ${\displaystyle \frac{-7}{15}÷\frac{-11}{15}}$

= ${\displaystyle \frac{-7}{15}\times \frac{15}{-11}}$

= ${\displaystyle \frac{7}{11}}$