document.write( "Question 114382This question is from textbook
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Algebra.Com's Answer #83607 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( " \"1%2Ax%2B1%2Ay=2\"
\n" ); document.write( " \"-3%2Ax%2B4%2Ay=36\"
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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=2-1%2Ax\"Subtract \"1%2Ax\" from both sides
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\n" ); document.write( " \"y=%282-1%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=2-1%2Ax\" Now we've fully isolated y
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\n" ); document.write( " Since y equals \"2-1%2Ax\" we can substitute the expression \"2-1%2Ax\" into y of the 2nd equation. This will eliminate y so we can solve for x.
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\n" ); document.write( " \"-3%2Ax%2B4%2Ahighlight%28%282-1%2Ax%29%29=36\" Replace y with \"2-1%2Ax\". Since this eliminates y, we can now solve for x.
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\n" ); document.write( " \"-3%2Ax%2B4%2A%282%29%2B4%28-1%29x=36\" Distribute 4 to \"2-1%2Ax\"
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\n" ); document.write( " \"-3%2Ax%2B8-4%2Ax=36\" Multiply
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\n" ); document.write( " \"-3%2Ax%2B8-4%2Ax=36\" Reduce any fractions
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\n" ); document.write( " \"-3%2Ax-4%2Ax=36-8\" Subtract \"8\" from both sides
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\n" ); document.write( " \"-3%2Ax-4%2Ax=28\" Combine the terms on the right side
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\n" ); document.write( " \"-7%2Ax=28\" Now combine the terms on the left side.
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\n" ); document.write( " \"cross%28%281%2F-7%29%28-7%2F1%29%29x=%2828%2F1%29%281%2F-7%29\" Multiply both sides by \"1%2F-7\". This will cancel out \"-7%2F1\" and isolate x
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\n" ); document.write( " So when we multiply \"28%2F1\" and \"1%2F-7\" (and simplify) we get
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\n" ); document.write( " \"x=-4\" <---------------------------------One answer
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\n" ); document.write( " Now that we know that \"x=-4\", lets substitute that in for x to solve for y
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\n" ); document.write( " \"-3%28-4%29%2B4%2Ay=36\" Plug in \"x=-4\" into the 2nd equation
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\n" ); document.write( " \"12%2B4%2Ay=36\" Multiply
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\n" ); document.write( " \"4%2Ay=36-12\"Subtract \"12\" from both sides
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\n" ); document.write( " \"4%2Ay=24\" Combine the terms on the right side
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\n" ); document.write( " \"cross%28%281%2F4%29%284%29%29%2Ay=%2824%2F1%29%281%2F4%29\" Multiply both sides by \"1%2F4\". This will cancel out 4 on the left side.
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\n" ); document.write( " \"y=24%2F4\" Multiply the terms on the right side
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\n" ); document.write( " \"y=6\" Reduce
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\n" ); document.write( " So this is the other answer
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\n" ); document.write( " \"y=6\"<---------------------------------Other answer
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\n" ); document.write( " So our solution is
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\n" ); document.write( " \"x=-4\" and \"y=6\"
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\n" ); document.write( " which can also look like
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\n" ); document.write( " (\"-4\",\"6\")
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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( " \"1%2Ax%2B1%2Ay=2\"
\n" ); document.write( " \"-3%2Ax%2B4%2Ay=36\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"1%2Ax%2B1%2Ay=2\" (red) and \"-3%2Ax%2B4%2Ay=36\" (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 (\"-4\",\"6\"). This verifies our answer.
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\n" ); document.write( " Plug in (\"-4\",\"6\") into the system of equations
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\n" ); document.write( " Let \"x=-4\" and \"y=6\". Now plug those values into the equation \"1%2Ax%2B1%2Ay=2\"
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\n" ); document.write( " \"1%2A%28-4%29%2B1%2A%286%29=2\" Plug in \"x=-4\" and \"y=6\"
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\n" ); document.write( " \"-4%2B6=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 (\"-4\",\"6\") satisfies \"1%2Ax%2B1%2Ay=2\"
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\n" ); document.write( " Let \"x=-4\" and \"y=6\". Now plug those values into the equation \"-3%2Ax%2B4%2Ay=36\"
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\n" ); document.write( " \"-3%2A%28-4%29%2B4%2A%286%29=36\" Plug in \"x=-4\" and \"y=6\"
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\n" ); document.write( " \"12%2B24=36\" Multiply
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\n" ); document.write( " \"36=36\" Add
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\n" ); document.write( " \"36=36\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"-4\",\"6\") satisfies \"-3%2Ax%2B4%2Ay=36\"
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\n" ); document.write( " Since the solution (\"-4\",\"6\") satisfies the system of equations
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\n" ); document.write( " \"1%2Ax%2B1%2Ay=2\"
\n" ); document.write( " \"-3%2Ax%2B4%2Ay=36\"
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\n" ); document.write( " this verifies our answer.
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