A simple math equation solving for unknown

  • Thread starter eXmag
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  • #1
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Homework Statement



Solve for A
27 = 81/√3a-3

Homework Equations





The Attempt at a Solution



Im not sure where to begin with this question. Can someone go through all the steps into solving for A. Thanks
 

Answers and Replies

  • #2
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Is it sqrt(3a - 3) or sqrt(3a) - 3 or sqrt(3) * a - 3.

Whatever value of "a" is in the denominator, it has to be moved to the numerator, usually by multiplying both sides of the equation by the appropriate term containing "a". If it's sqrt(3a - 3) then multiply both sides of the equation by sqrt (3a - 3) to get:

27 * sqrt(3a - 3) = 81.

Then continue to solve for "a".
 
  • #3
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Multiply both sides by sqrt(3a-3). It should be pretty straightforward from there
Edit:never mind someone else answered it first
 
  • #4
SammyS
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Homework Statement



Solve for A
27 = 81/√3a-3

Homework Equations



The Attempt at a Solution



I'm not sure where to begin with this question. Can someone go through all the steps into solving for A. Thanks
Begin by using enough sets of parentheses to make the problem unambiguous.

Is it

[itex]\displaystyle 27=\frac{81}{\sqrt{3a-3\,}}[/itex]

or

[itex]\displaystyle 27=\frac{81}{\sqrt{3a\,}-3}[/itex]

or

[itex]\displaystyle 27=\frac{81}{\sqrt{3\,}\,a-3}[/itex]

or

[itex]\displaystyle 27=\frac{81}{\sqrt{3a\,}}-3[/itex]


or what it means literally with there being no parentheses

[itex]\displaystyle 27=\frac{81}{\sqrt{3\,}}a-3[/itex]

    ?
 
  • #5
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yes I should have mentioned it is square root 3a-3 not square root 3a then minus 3. Ok thanks for the responses.
 
  • #6
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^the first example you gave sammy, how would I go through the steps to solve for A?
 
  • #7
SammyS
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Isolate the radical.

Square both sides.
 
  • #8
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Ok, sorry Im not really math literate. How would you isolate the radical?
 
  • #9
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ok so im gonna go through it.

27 x √3a-3 = 81
√3a-3 = 81/27
√3a-3 = 3
3a-3 = 9
3a = 9 + 3
3a = 12
a = 12/3
a = 4
 
  • #10
SammyS
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ok so im gonna go through it.

27 x √3a-3 = 81
√3a-3 = 81/27
√3a-3 = 3
3a-3 = 9
3a = 9 + 3
3a = 12
a = 12/3
a = 4
Now, check your answer by plugging into the original problem.
 
  • #11
36
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perfect...thank you very much sammy!
 

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