2. \( \left(1 / 3 a b^{3}\right)\left(-2 / 5 a^{3} b c\right)= \)

To solve \( \left(1 / 3 a b^{3}\right)\left(-2 / 5 a^{3} b c\right) \), we start by multiplying the coefficients and the variables separately. First, multiply the coefficients: \[ \frac{1}{3} \cdot \left(-\frac{2}{5}\right) = -\frac{2}{15} \] Next, combine the variables. For \( a \): \[ a^{1} \cdot a^{3} = a^{1+3} = a^{4} \] For \( b \): \[ b^{3} \cdot b^{1} = b^{3+1} = b^{4} \] And for \( c \): Since there is one \( c \) only in the second part of the equation, it will be included in the final result. Putting it all together, the complete expression becomes: \[ -\frac{2}{15} a^{4} b^{4} c \] So, the answer is: \[ -\frac{2}{15} a^{4} b^{4} c \]