Divide 4 throughout the fraction, which gives \(\frac{12 \div 4}{16 \div 4} = \frac{3}{4}\).

\(\frac{{{a^2}b}}{{a{b^2}}} = \frac{{a \times a \times b}}{{a \times b \times b}}\) Since a and b are both factors, cancel this fraction by dividing by both a and b ...