SOLUTION: Am working on a problem for a spreadsheet design and modeling class and need to use simple algebra to solve the following problem: 9Xi + 6(200 - Xi) =1,566 The answer is 122,

Algebra ->  Equations -> SOLUTION: Am working on a problem for a spreadsheet design and modeling class and need to use simple algebra to solve the following problem: 9Xi + 6(200 - Xi) =1,566 The answer is 122,      Log On


   

Question 480835: Am working on a problem for a spreadsheet design and modeling class and need to use simple algebra to solve the following problem:
9Xi + 6(200 - Xi) =1,566
The answer is 122, but I would like to know how the answer was determined.
Thank you Don at wvudonpost@aol.com
Found 2 solutions by mathstutor494, Theo:
Answer by mathstutor494(120) About Me  (Show Source):
You can put this solution on YOUR website!
9Xi + 6(200 - Xi) =1,566
9Xi + 1200 - 6Xi =1,566
Rearranging similar terms
9Xi-6Xi=1566 - 1200
3Xi = 366
Dividing both sides by 3 results in
Xi = 122

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
treat xi like it was a variable.
it's simpler to just call it x.
your problem is solved in the following manner:
original equation is:
9x + 6(200-x) = 1566
simplify by removing parentheses to get:
9x + 1200-6x = 1566
subtract 1200 from both sides of the equation to get:
9x - 6x = 1566 - 1200
combine like terms to get:
3x = 366
divide both sides of the equation by 3 to get:
x = 122
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i suspect xi is really the ith element in the x array.
as such, it would be denoted as x[i] or xi
that doesn't really matter.
the algebra is the same whether you are operating on x or xi or x[i] or xi