Let's simplify the expression step-by-step.

Given:
\[
(-0.3)^{10} \times \frac{15^5}{25^3} \times (-0.9)^7
\]

### Step 1: Calculate each component

1. **Calculate \((-0.3)^{10}\)**:
\[
(-0.3)^{10} = 0.3^{10} \quad (\text{since raising a negative number to an even power gives a positive result})
\]
\[
0.3^{10} = (3 \times 10^{-1})^{10} = 3^{10} \times 10^{-10} = 59049 \times 10^{-10} = 5.9049 \times 10^{-6}
\]

2. **Calculate \( \frac{15^5}{25^3} \)**:
- First, express this in terms of powers:
\[
15 = 3 \times 5 \quad \text{and} \quad 25 = 5^2
\]
\[
15^5 = (3 \times 5)^5 = 3^5 \times 5^5
\]
\[
25^3 = (5^2)^3 = 5^6
\]
Thus,
\[
\frac{15^5}{25^3} = \frac{3^5 \times 5^5}{5^6} = 3^5 \times 5^{-1} = 3^5 \times \frac{1}{5}
\]
Calculating \(3^5\):
\[
3^5 = 243
\]
Therefore,
\[
\frac{15^5}{25^3} = \frac{243}{5} = 48.6
\]

3. **Calculate \((-0.9)^7\)**:
\[
(-0.9)^7 = -0.9^7 \quad (\text{since raising a negative number to an odd power gives a negative result})
\]
Calculating \(0.9^7\):
\[
0.9^7 = (9 \times 10^{-1})^7 = 9^7 \times 10^{-7}
\]
\(9^7 = 4782969\) (This can be calculated more easily using exponent rules or a calculator)
Thus:
\[
0.9^7 = 4782969 \times 10^{-7} = 4.782969 \times 10^{-1}
\]
Hence,
\[
(-0.9)^7 = -4.782969 \times 10^{-1}
\]

### Step 2: Combine all components
Substituting the values back, we have:
\[
= (5.9049 \times 10^{-6}) \times (48.6) \times (-4.782969 \times 10^{-1})
\]

Now multiply these together:
- First, calculate \(5.9049 \times 10^{-6} \times 48.6\):
\[
= 0.000287 (approximately)
\]

- Now multiply that result by \(-4.782969 \times 10^{-1}\):
\[
0.000287 \times (-0.4782969) \approx -0.0001373 \text{ (approximately)}
\]

Therefore, the final answer is approximately:
\[
-0.0001373
\]

The final answer to \((-0.3)^{10} \times \dfrac{15^5}{25^3} \times (-0.9)^7\) is approximately \(-0.0001373\).