Tính: 5 14/17.(-3 1/4) 6 3/17.(-3 1/4)

Lời giải:

\[5\frac{{14}}{{17}} \cdot \left( { - 3\frac{1}{4}} \right) + 6\frac{3}{{17}} \cdot \left( { - 3\frac{1}{4}} \right)\]

\[ = \left( { - 3\frac{1}{4}} \right) \cdot \left( {5\frac{{14}}{{17}} + 6\frac{3}{{17}}} \right)\]

\[ =  - \frac{{13}}{4} \cdot \left( {5 + \frac{{14}}{{17}} + 6 + \frac{3}{{17}}} \right)\]

\[ =  - \frac{{13}}{4} \cdot \left( {11 + 1} \right)\]

\[ =  - \frac{{13}}{4} \cdot 12 =  - 39\]