г) 35x^4/18y^2 * 9y/14x^2 ;

г) $$\frac{35x^4}{18y^2} \cdot \frac{9y}{14x^2} = \frac{35x^4 \cdot 9y}{18y^2 \cdot 14x^2} = \frac{315x^4y}{252x^2y^2} = \frac{5x^2}{4y}$$

Ответ: $$\frac{5x^2}{4y}$$