Answer
$1; \lt -3,0,-4 \gt$
Work Step by Step
Here, $|v|=\sqrt{(\dfrac{3}{5})^2+0^2+(\dfrac{4}{5})^2}=1$
The unit vector $\hat{\textbf{u}}$ can be calculated as: $\hat{\textbf{u}}=\dfrac{v}{|v|}$
Now, $-5 \hat{\textbf{u}}=-5 [\dfrac{\lt \dfrac{3}{5},0,\dfrac{4}{5} \gt}{1}]= \lt -3,0,-4 \gt$
Thus, our final answers are: $1; \lt -3,0,-4 \gt$
