The correct answer is: [A]: " 15.75 * 10⁷ " .
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The problem is:
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"What is: "(2.5 * 10²) (6.3 * 10⁵)" (in scientific notation)?
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(2.5 * 10²) (6.3 * 10⁵) =
2.5 * 10² * 6.3 * 10⁵ =
2.5 * 6.3 * 10² * 10⁵
= 2.5 * 6.3 * 10⁽² ⁺ ⁵) =
= 2.5 * 6.3 * 10⁷ ;
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Note the following property of exponents:
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xᵃ * xᵇ = x ⁽ᵃ ⁺ ᵇ⁾ ;
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Thus: 10² * 10⁵ = 10⁽² ⁺ ⁵) = 10⁷ ;
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So; we have:
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2.5 * 6.3 * 10⁷ ;
→ 2.5 * 6.3 * 10⁷ = (2.5 * 6.3) * 10⁷ = 15.75 * 10⁷ .
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The answer is: [A]: " 15.75 * 10⁷ " .
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