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If 53x-1÷25=125, find the value of x. - Mathematics

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Question

If `5^(3x - 1) ÷ 25 = 125`, find the value of x.

Sum
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Solution

Given, `5^(3x - 1) ÷ 25 = 125`

∵ 25 = 5 × 5 = 52

And 125 = 5 × 5 × 5 = 53

∴ `5^(3x - 1) ÷ (5)^2 = (5)^3`

⇒ `(5)^(3x - 1 - 2) = 5^3`  ...[∵ am ÷ an = (a)m – n]

⇒ `5^(3x - 3) = (5)^3`

On comparing both sides, we get

3x – 3 = 3

⇒ 3x = 6

⇒ x = 2

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Chapter 8: Exponents and Powers - Exercise [Page 259]

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NCERT Exemplar Mathematics [English] Class 8
Chapter 8 Exponents and Powers
Exercise | Q 105. | Page 259

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