Evaluate: a. `21 xx (45)/( 49)`

Answer

To evaluate the expression \( 21 \times \frac{45}{49} \), we will follow these steps:

### Step 1: Rewrite the expression
We can rewrite the expression as:
\[ \frac{21 \times 45}{49} \]

### Step 2: Simplify the fraction
Next, we notice that both 21 and 49 can be divided by 7:
- \( 21 \div 7 = 3 \)
- \( 49 \div 7 = 7 \)

So, we can rewrite the expression as:
\[ \frac{3 \times 45}{7} \]

### Step 3: Multiply the numerator
Now, we multiply the numbers in the numerator:
\[ 3 \times 45 = 135 \]

### Step 4: Write the final fraction
Now we can write the expression as:
\[ \frac{135}{7} \]

### Final Answer
Thus, the evaluated expression is:
\[ \frac{135}{7} \]

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