SOLUTION: I don't understand how to work this problem which is on page 408 systems of linear equations by substitution the problems is y=3x x=3y

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Question 129601This question is from textbook Algebra 1
: I don't understand how to work this problem which is on page 408 systems of linear equations by substitution the problems is y=3x x=3yThis question is from textbook Algebra 1

Answer by bucky(2100) About Me  (Show Source):
You can put this solution on YOUR website!
Given to solve:
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y+=+3x and
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x+=+3y
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The second equation is solved for x. It says that x equals 3y. So you can take 3y and substitute
it for x in the first equation. When you do, the first equation becomes:
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y+=+3%2A%283y%29+=+9y
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So this equation is:
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y+=+9y
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The only real value of y that will satisfy this equation is y = 0. If y does equal zero,
then both sides of the equation y+=+9y are equal to zero. Another way to look at this
is to start with:
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y+-+9y
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Subtract y from both sides and you have:
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0+=+8y
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Solve for y by dividing both sides by 8 and you have:
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0+=+y
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Now that you know y equals zero you can return to either of the two equations you were
originally given and substitute 0 for y. If you do, you will find that x also equals zero.
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So the common solution for these two equations is (0, 0) meaning that the graphs of the two
equations intersect at the origin.
.
Hope this helps you to understand the problem.
.