Evaluate:
`(8.6)^(2)-(1.4)^(2)`

Answer

To evaluate the expression \( (8.6)^2 - (1.4)^2 \), we can use the algebraic identity for the difference of squares, which states:

\[ A^2 - B^2 = (A + B)(A - B) \]

### Step-by-step Solution:

1. **Identify A and B**:
- Let \( A = 8.6 \)
- Let \( B = 1.4 \)

2. **Apply the difference of squares formula**:
- According to the formula, we can rewrite the expression:
\[ (8.6)^2 - (1.4)^2 = (8.6 + 1.4)(8.6 - 1.4) \]

3. **Calculate \( A + B \)**:
- Calculate \( 8.6 + 1.4 \):
\[ 8.6 + 1.4 = 10.0 \]

4. **Calculate \( A - B \)**:
- Calculate \( 8.6 - 1.4 \):
\[ 8.6 - 1.4 = 7.2 \]

5. **Multiply the results**:
- Now substitute back into the expression:
\[ (8.6)^2 - (1.4)^2 = (10.0)(7.2) \]
- Calculate \( 10.0 \times 7.2 \):
\[ 10.0 \times 7.2 = 72.0 \]

6. **Final Result**:
- Therefore, the evaluated result of \( (8.6)^2 - (1.4)^2 \) is:
\[ \boxed{72} \]