document.write( "Question 120364: solve the system of equations using the substitution mehtod\r
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Algebra.Com's Answer #88229 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
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Solved by pluggable solver: Solving a linear system of equations by subsitution

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\n" ); document.write( " Lets start with the given system of linear equations
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\n" ); document.write( " \"3%2Ax%2B1%2Ay=2\"
\n" ); document.write( " \"2%2Ax-1%2Ay=3\"
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\n" ); document.write( " Now in order to solve this system by using substitution, we need to solve (or isolate) one variable. I'm going to choose y.
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\n" ); document.write( " Solve for y for the first equation
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\n" ); document.write( " \"1%2Ay=2-3%2Ax\"Subtract \"3%2Ax\" from both sides
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\n" ); document.write( " \"y=%282-3%2Ax%29\" Divide both sides by 1.
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\n" ); document.write( " Which breaks down and reduces to
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\n" ); document.write( " \"y=2-3%2Ax\" Now we've fully isolated y
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\n" ); document.write( " Since y equals \"2-3%2Ax\" we can substitute the expression \"2-3%2Ax\" into y of the 2nd equation. This will eliminate y so we can solve for x.
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\n" ); document.write( " \"2%2Ax%2B-1%2Ahighlight%28%282-3%2Ax%29%29=3\" Replace y with \"2-3%2Ax\". Since this eliminates y, we can now solve for x.
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\n" ); document.write( " \"2%2Ax-1%2A%282%29-1%28-3%29x=3\" Distribute -1 to \"2-3%2Ax\"
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\n" ); document.write( " \"2%2Ax-2%2B3%2Ax=3\" Multiply
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\n" ); document.write( " \"2%2Ax-2%2B3%2Ax=3\" Reduce any fractions
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\n" ); document.write( " \"2%2Ax%2B3%2Ax=3%2B2\"Add \"2\" to both sides
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\n" ); document.write( " \"2%2Ax%2B3%2Ax=5\" Combine the terms on the right side
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\n" ); document.write( " \"5%2Ax=5\" Now combine the terms on the left side.
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\n" ); document.write( " \"cross%28%281%2F5%29%285%2F1%29%29x=%285%2F1%29%281%2F5%29\" Multiply both sides by \"1%2F5\". This will cancel out \"5%2F1\" and isolate x
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\n" ); document.write( " So when we multiply \"5%2F1\" and \"1%2F5\" (and simplify) we get
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\n" ); document.write( " \"x=1\" <---------------------------------One answer
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\n" ); document.write( " Now that we know that \"x=1\", lets substitute that in for x to solve for y
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\n" ); document.write( " \"2%281%29-1%2Ay=3\" Plug in \"x=1\" into the 2nd equation
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\n" ); document.write( " \"2-1%2Ay=3\" Multiply
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\n" ); document.write( " \"-1%2Ay=3-2\"Subtract \"2\" from both sides
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\n" ); document.write( " \"-1%2Ay=1\" Combine the terms on the right side
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\n" ); document.write( " \"cross%28%281%2F-1%29%28-1%29%29%2Ay=%281%2F1%29%281%2F-1%29\" Multiply both sides by \"1%2F-1\". This will cancel out -1 on the left side.
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\n" ); document.write( " \"y=1%2F-1\" Multiply the terms on the right side
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\n" ); document.write( " \"y=-1\" Reduce
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\n" ); document.write( " So this is the other answer
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\n" ); document.write( " \"y=-1\"<---------------------------------Other answer
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\n" ); document.write( " So our solution is
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\n" ); document.write( " \"x=1\" and \"y=-1\"
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\n" ); document.write( " which can also look like
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\n" ); document.write( " (\"1\",\"-1\")
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\n" ); document.write( " Notice if we graph the equations (if you need help with graphing, check out this solver)
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\n" ); document.write( " \"3%2Ax%2B1%2Ay=2\"
\n" ); document.write( " \"2%2Ax-1%2Ay=3\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"3%2Ax%2B1%2Ay=2\" (red) and \"2%2Ax-1%2Ay=3\" (green) (hint: you may have to solve for y to graph these) intersecting at the blue circle.
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\n" ); document.write( " and we can see that the two equations intersect at (\"1\",\"-1\"). This verifies our answer.
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\n" ); document.write( " Check:
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\n" ); document.write( " Plug in (\"1\",\"-1\") into the system of equations
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\n" ); document.write( " Let \"x=1\" and \"y=-1\". Now plug those values into the equation \"3%2Ax%2B1%2Ay=2\"
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\n" ); document.write( " \"3%2A%281%29%2B1%2A%28-1%29=2\" Plug in \"x=1\" and \"y=-1\"
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\n" ); document.write( " \"3-1=2\" Multiply
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\n" ); document.write( " \"2=2\" Add
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\n" ); document.write( " \"2=2\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"1\",\"-1\") satisfies \"3%2Ax%2B1%2Ay=2\"
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\n" ); document.write( " Let \"x=1\" and \"y=-1\". Now plug those values into the equation \"2%2Ax-1%2Ay=3\"
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\n" ); document.write( " \"2%2A%281%29-1%2A%28-1%29=3\" Plug in \"x=1\" and \"y=-1\"
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\n" ); document.write( " \"2%2B1=3\" Multiply
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\n" ); document.write( " \"3=3\" Add
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\n" ); document.write( " \"3=3\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"1\",\"-1\") satisfies \"2%2Ax-1%2Ay=3\"
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\n" ); document.write( " Since the solution (\"1\",\"-1\") satisfies the system of equations
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\n" ); document.write( " \"3%2Ax%2B1%2Ay=2\"
\n" ); document.write( " \"2%2Ax-1%2Ay=3\"
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\n" ); document.write( " this verifies our answer.
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