Surds and Indices Practice Test 2

Question : 8 of 17

Marks: +1, -0

Given that

3 ^{x- y } = 27

and

3^{x+y} =243

, then x is equal to:

Solution:

3^(x- y) = 27 ⇒3^(x - y) = 3^3

⇒ x - y = 3

...(i)
Again,

3^(x + y) = 243

⇒3^(x + y) = 3^5⇒x + y = 5

...(ii)
Solving equations (i) & (ii) we get,

x = 4

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