rite2deepti wrote:

If 25(5^x) = 1 then x=

A. –2

B. –1

C. 0

D. 1

E. 2

I have probelm with this question .

I solved it like 5^2(5^x)=1

2+x=1

X=-1

But my answer is wrong or the answer from the source is wrong please help ....

Hey Deepti,

You have solved the question correctly till this point:

\(5^{(2+x)} = 1\)

But please remember that while equating the powers from LHS and RHS, the base should be the same. In the LHS, the base is 5 and on the right hand side(RHS), the base is 1, so we need to convert 1 to the base 5, which can be easily done, by write 1 as \(5^0\)

Now you will have \(5^{(2+x)} = 5^0\)

After this, you can equate the powers, which will give you \(2 + x = 0\) and \(x = -2\)

I hope this clears your doubt.

Regards,

Saquib

e-GMATQuant Expert

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Ace GMAT quant

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