3. Реши уравнение: а) b - 13/15 = 13/45; б) 7,36d - 3,6d = 39,48.

Решим уравнения:

1. $$b - \frac{13}{15} = \frac{13}{45}$$ $$b = \frac{13}{45} + \frac{13}{15}$$ $$b = \frac{13}{45} + \frac{13 \cdot 3}{15 \cdot 3}$$ $$b = \frac{13}{45} + \frac{39}{45}$$ $$b = \frac{13+39}{45}$$ $$b = \frac{52}{45}$$
2. $$7,36d - 3,6d = 39,48$$ $$(7,36 - 3,6)d = 39,48$$ $$3,76d = 39,48$$ $$d = \frac{39,48}{3,76}$$ $$d = 10,5$$

Ответ:

1. $$ b = \frac{52}{45} $$
2. $$ d = 10,5 $$