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Evaluate the following without directly ...

Evaluate the following without directly multiplying :
`102 xx 105`

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The correct Answer is:
To evaluate \( 102 \times 105 \) without directly multiplying, we can use the algebraic identity for the product of two binomials. Here’s how we can do it step by step: ### Step-by-Step Solution: 1. **Rewrite the Numbers**: We can express \( 102 \) and \( 105 \) in terms of \( 100 \): \[ 102 = 100 + 2 \] \[ 105 = 100 + 5 \] 2. **Use the Algebraic Identity**: We can apply the identity \( (x + a)(x + b) = x^2 + (a + b)x + ab \). Here, we can set: - \( x = 100 \) - \( a = 2 \) - \( b = 5 \) 3. **Calculate \( x^2 \)**: First, calculate \( x^2 \): \[ x^2 = 100^2 = 10000 \] 4. **Calculate \( a + b \)**: Next, calculate \( a + b \): \[ a + b = 2 + 5 = 7 \] 5. **Calculate \( ab \)**: Now, calculate \( ab \): \[ ab = 2 \times 5 = 10 \] 6. **Combine the Results**: Substitute these values back into the identity: \[ (100 + 2)(100 + 5) = 10000 + (7 \times 100) + 10 \] \[ = 10000 + 700 + 10 \] \[ = 10710 \] Thus, the final answer is: \[ \boxed{10710} \]
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