Algebra-6 (FMS-2009)

If log₇log₅ (√(x+5) + √x) = 0, what is the value of x?               

(1)2                (2)3                (3)4               (4)5

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Solution:

It’s a simpler one. Checking answer options will do here.

Considering  √(x+5), for this 4 is looking suitable as √(4+5) = √9 = 3

Hence check for x =4 => log₇log₅ (√(4+5) + √4) = log₇log₅ (3 + 2)

= log₇log₅ (5) = log₇1 = 0, satisfied..

Answer (3)