SOLUTION: please help, if I use the gauss-jordan elimination to solve the equation, how do i find the answer: 3x+5y=7 6x-y=-8?

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Question 176533: please help, if I use the gauss-jordan elimination to solve the equation, how do i find the answer: 3x+5y=7 6x-y=-8?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

First, extract the coefficients and the right hand constants to form the matrix:


%28matrix%282%2C3%2C3%2C5%2C7%2C6%2C-1%2C-8%29%29


Multiply Row 1 by 1%2F3 to make the pivot 1:

%28matrix%282%2C3%2C1%2C5%2F3%2C7%2F3%2C6%2C-1%2C-8%29%29


Add -6*Row 1 to Row 2 to get the new Row 2

%28matrix%282%2C3%2C1%2C5%2F3%2C7%2F3%2C0%2C-11%2C-22%29%29


Multiply Row 2 by -1%2F11 to make the pivot 1:

%28matrix%282%2C3%2C1%2C5%2F3%2C7%2F3%2C0%2C1%2C2%29%29




Add -5%2F3*Row 2 to Row 1 to replace Row 1:

%28matrix%282%2C3%2C1%2C0%2C-1%2C0%2C1%2C2%29%29


The matrix is now in reduced row echelon form


If you need more help with row reduction, check out the Linear Algebra Toolkit



Since the right hand column is %28matrix%282%2C1%2C-1%2C2%29%29, this means that x=-1 and y=2