Представим в виде многочлена:
- a) $$\frac{2}{7}x(1.4x^2 - 3.5y) = \frac{2}{7}x(\frac{14}{10}x^2 - \frac{35}{10}y) = \frac{2}{7} \cdot \frac{14}{10} x^3 - \frac{2}{7} \cdot \frac{35}{10} xy = \frac{28}{70}x^3 - \frac{70}{70}xy = \frac{2}{5}x^3 - xy$$
- б) $$\frac{-1}{3}c^2(1.2d^2 - 6c) = -\frac{1}{3}c^2(\frac{12}{10}d^2 - 6c) = -\frac{1}{3} \cdot \frac{12}{10} c^2d^2 + \frac{1}{3} \cdot 6c^3 = -\frac{12}{30}c^2d^2 + 2c^3 = -\frac{2}{5}c^2d^2 + 2c^3$$
Ответ:
- a) $$\frac{2}{5}x^3 - xy$$
- б) $$-{\frac{2}{5}}c^2d^2 + 2c^3$$