90 square - 3 square -93x find the value of x
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Step-by-step explanation:
Take 3^x common from both 3^(x-1) and 3^(x+1) as the first step. After that solve the equation.
Here I shall use a basic concept of Index ::--
if a^x = a^m [ a≠1 ] then x=m [ where x is a variable and m is a real number ]
If a=1 , then x may or may not equal to m .
NOW,
3^(x-1) + 3^(x+1) = 90 , [ taking 3^x common ]
=> (⅓ + 3) • 3^x = 90 ,
=> 10/3 • 3^x = 90 ,
=> 3^x = 90 • 3/10 = 270/10 = 27 ,
=> 3^x = 3³
=> x=3 [ from the basic concept of index mentioned above ]
So the value of x is 3 .
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ok so learn formula properly
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