If 3 x+1= 81 , then x-1=

GMAT Quantitative Reasoning Practice Test 1

Question : 63 of 100

Marks: +1, -0

3 x+1=

81 , then

x-1=

Solution:

Solve for

x

first. Since

3 x+1=81

, and 81 is 34 , make an easier equation just based on the exponents. This would be

x+1=4 . x=3

. Therefore,

x-1=3-1=2

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