How do you solve $3(x+3)^(3/4)= 81$ ?

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Answer 1 · 2015-04-10T18:56:04

Simply divide by $3$ :

$(x+3)^(3/4) = 27$

Raise everything to the $4/3$ to multiply by the $3/4$ to get $1$ :

$x+3 = 27^(4/3)$

And subtract $3$ .

$x = 27^(4/3) - 3 = 3^(3*4/3) - 3 = 3^4 - 3 = 78$

To check:
$(78+3) ^(3/4) = 27$
$81^(3/4) = 27$
$3^3 = 27$

How do you solve 3(x+3)^(3/4)= 813(x+3)^(3/4)= 81?