`(.6xx.6xx.6+.4xx.4xx.4+3xx.6xx.4xx(.6+.4)=`

Options

A. 21.736
B. 2.1736
C. 0.21736
D. 1

Answer

To solve the expression \(0.6 \times 0.6 \times 0.6 + 0.4 \times 0.4 \times 0.4 + 3 \times 0.6 \times 0.4 \times (0.6 + 0.4)\), we can follow these steps:

### Step 1: Identify the components of the expression
The expression consists of three parts:
1. \(0.6 \times 0.6 \times 0.6\)
2. \(0.4 \times 0.4 \times 0.4\)
3. \(3 \times 0.6 \times 0.4 \times (0.6 + 0.4)\)

### Step 2: Calculate each part
1. **Calculate \(0.6 \times 0.6 \times 0.6\)**:
\[ 0.6 \times 0.6 = 0.36 \]
\[ 0.36 \times 0.6 = 0.216 \]

2. **Calculate \(0.4 \times 0.4 \times 0.4\)**:
\[ 0.4 \times 0.4 = 0.16 \]
\[ 0.16 \times 0.4 = 0.064 \]

3. **Calculate \(3 \times 0.6 \times 0.4 \times (0.6 + 0.4)\)**:
\[ 0.6 + 0.4 = 1.0 \]
\[ 3 \times 0.6 \times 0.4 \times 1.0 = 3 \times 0.6 \times 0.4 \]
\[ 0.6 \times 0.4 = 0.24 \]
\[ 3 \times 0.24 = 0.72 \]

### Step 3: Combine all parts
Now we add all the calculated parts together:
\[ 0.216 + 0.064 + 0.72 = 1.0 \]

### Final Answer
Thus, the final value of the expression is:
\[ \boxed{1} \]