a) \(\displaystyle {3 \over {x + 2}} = {{3\left( {x - 1} \right)} \over {\left( {x + 2} \right)\left( {x - 1} \right)}} \)\(\,\displaystyle = {{3x - 3} \over {{x^2} + x - 2}} \)
\(\displaystyle {{x - 1} \over {5x}} = {{3\left( {x - 1} \right)} \over {5x.3}} = {{3x - 3} \over {15x}} \)
b) \(\dfrac{{x + 5}}{{4x}} = \dfrac{{\left( {x + 5} \right)\left( {x - 5} \right)}}{{4x\left( {x - 5} \right)}} \)\(\,= \dfrac{{{x^2} - 25}}{{4{x^2} - 20x}}\)
\(=\dfrac{{{x^2} - 25}}{{2x + 3}}\)
