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If 3 2 X − 8 225 = 5 3 5 X , Then X = - Mathematics

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Question

If \[\frac{3^{2x - 8}}{225} = \frac{5^3}{5^x},\]  then x =

Options

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  • 5

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MCQ

Solution

We have to find the value of x  provided  \[\frac{3^{2x - 8}}{225} = \frac{5^3}{5^x},\]

So,

\[\frac{3^{2x - 8}}{3^2 × 5^2} = \frac{5^3}{5^x}\]

By cross multiplication we get 

`3^(2x-8) xx 5^x = 3^2xx5^2 xx5^3`

By equating exponents we get 

`3^(2x-8) = 3^2`

`2x - 8 = 2`

`2x= 2+8`

`2x = 10`

`x=10/2`

`x=5`

And 

`5^x = 5^(3+2)`

`x=3+2`

`x=5`

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Chapter 2: Exponents of Real Numbers - Exercise 2.4 [Page 32]

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RD Sharma Mathematics [English] Class 9
Chapter 2 Exponents of Real Numbers
Exercise 2.4 | Q 30 | Page 32

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