Question

Express $\frac{-3}{5}$ as a rational number with denominator ?

(i) 20 (ii) -30 (iii) 35 (iv) -40

Answer 1

(i) $20=5\times 4$

$\therefore \frac{-3}{5}=\frac{-3\times 4}{5\times 4}$ (Multiplying numerator and denominator by 4)

$=\frac{-12}{20}$

(ii) $-30=5\times (-6)$

$\therefore \frac{-3}{5}=\frac{-3(-6)}{5(-6)}$ [Multiplying numerator and denominator by (-6)]

$=\frac{18}{-30}$

(iii) $35=5\times 7$

$\therefore \frac{-3}{5}=\frac{-3\times 7}{5\times 7}$ (Multiplying the numerator and denominator by 7)

$=\frac{-21}{35}$

(iv) $-40=5\times (-8)$

$\therefore \frac{-3}{5}=\frac{-3\times (-8)}{5\times (-8)}$ (Multiplying the numerator and denominator by (-8)

$=\frac{24}{-40}$