Решение уравнений

a) $$(x + 4x) \cdot 8 = 89.2$$ $$5x \cdot 8 = 89.2$$ $$40x = 89.2$$ $$x = \frac{89.2}{40}$$ $$x = 2.23$$

б) $$x - 12 \frac{15}{42} = 3 \frac{28}{42}$$ $$x = 3 \frac{28}{42} + 12 \frac{15}{42}$$ $$x = 15 \frac{43}{42}$$ $$x = 16 \frac{1}{42}$$