To find the y-value of the function \( y = 3(5)^x \) when \( x = -6 \), we can substitute \(-6\) into the equation:
\[ y = 3(5)^{-6} \]
Now, we calculate \( (5)^{-6} \):
\[ (5)^{-6} = \frac{1}{5^6} = \frac{1}{15625} \]
Now, substituting this back into the equation:
\[ y = 3 \times \frac{1}{15625} = \frac{3}{15625} \]
Now we can present this as a fraction:
\[ y \approx 0.000192 (rounded to six decimal places) \]
Thus, the point when \( x = -6\) is:
\[ (-6, \frac{3}{15625}) \quad \text{or} \quad (-6, 0.000192) \]
So the completed point is:
\[ (-6, 0.000192) \]