If \(3^{-x}+3^{-x}+3^{-x}=1,\) what is the value of \(x?\)

Jay@ManhattanReview: GMAT Instructor; Posts: 3008; Joined: Mon Aug 22, 2016 6:19 am; Location: Grand Central / New York; Thanked: 470 times; Followed by:34 members

Re: If \(3^{-x}+3^{-x}+3^{-x}=1,\) what is the value of \(x?\)

by Jay@ManhattanReview » Wed Jul 22, 2020 11:10 pm

Vincen wrote: ↑
Wed Jul 22, 2020 12:40 pm
If \(3^{-x}+3^{-x}+3^{-x}=1,\) what is the value of \(x?\)

A. -1

B. -1/2

C. 1/3

D. 1/2

E. 1

[spoiler]OA=E[/spoiler]

Source: Magoosh

So, we have \(3^{-x}+3^{-x}+3^{-x}=1\)

\(3\times3^{-x}=1\)

\(3^{-x+1}=3^0\)

=> -x + 1 = 0

x = 1

Correct answer: E

Hope this helps!

-Jay
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Scott@TargetTestPrep: GMAT Instructor; Posts: 8086; Joined: Sat Apr 25, 2015 10:56 am; Location: Los Angeles, CA; Thanked: 43 times; Followed by:29 members

Re: If \(3^{-x}+3^{-x}+3^{-x}=1,\) what is the value of \(x?\)

by Scott@TargetTestPrep » Sat Jul 25, 2020 2:17 pm

Vincen wrote: ↑
Wed Jul 22, 2020 12:40 pm
If \(3^{-x}+3^{-x}+3^{-x}=1,\) what is the value of \(x?\)

A. -1

B. -1/2

C. 1/3

D. 1/2

E. 1

[spoiler]OA=E[/spoiler]