If (7)^{3x} = 343 then what is the value of (7)^{-2x} ?

RRB Group D Model Paper 2 with solutions

Question : 49 of 100

Marks: +1, -0

(7)^{3x}

= 343 then what is the value of

(7)^{-2x}

Solution:

(1) The given expression is:

(7)^{3x}

= 343
It can be written as

(7^x)^{3 }=(7)^3

Comparing both sides, we get:

(7)^{x}=(7)^{1}

Again, comparing both sides, we get:
x = 1
∴

(7)^{-2x}=7^{-2×1}

(7)^{-2}=149

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