document.write( "Question 120285: Solve each system of equations. Check by substitution\r
\n" ); document.write( "\n" ); document.write( "5x + 3t = 19
\n" ); document.write( "5x - 3t = 1\r
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Algebra.Com's Answer #88162 by MathLover1(20849)\"\" \"About 
You can put this solution on YOUR website!
\"5x+%2B+3t+=+19\"
\n" ); document.write( "\"5x+-+3t+=++1\".............let \"t=y\"\r
\n" ); document.write( "\n" ); document.write( "then you have:\r
\n" ); document.write( "\n" ); document.write( "\"5x+%2B+3y+=+19\"
\n" ); document.write( "\"5x+-+3y+=++1\"\r
\n" ); document.write( "\n" ); document.write( "solution:\r
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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( " \"5%2Ax%2B3%2Ay=19\"
\n" ); document.write( " \"5%2Ax-3%2Ay=1\"
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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( " \"3%2Ay=19-5%2Ax\"Subtract \"5%2Ax\" from both sides
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\n" ); document.write( " \"y=%2819-5%2Ax%29%2F3\" Divide both sides by 3.
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\n" ); document.write( " Which breaks down and reduces to
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\n" ); document.write( " \"y=19%2F3-%285%2F3%29%2Ax\" Now we've fully isolated y
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\n" ); document.write( " Since y equals \"19%2F3-%285%2F3%29%2Ax\" we can substitute the expression \"19%2F3-%285%2F3%29%2Ax\" into y of the 2nd equation. This will eliminate y so we can solve for x.
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\n" ); document.write( " \"5%2Ax%2B-3%2Ahighlight%28%2819%2F3-%285%2F3%29%2Ax%29%29=1\" Replace y with \"19%2F3-%285%2F3%29%2Ax\". Since this eliminates y, we can now solve for x.
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\n" ); document.write( " \"5%2Ax-3%2A%2819%2F3%29-3%28-5%2F3%29x=1\" Distribute -3 to \"19%2F3-%285%2F3%29%2Ax\"
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\n" ); document.write( " \"5%2Ax-57%2F3%2B%2815%2F3%29%2Ax=1\" Multiply
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\n" ); document.write( " \"5%2Ax-19%2B5%2Ax=1\" Reduce any fractions
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\n" ); document.write( " \"5%2Ax%2B5%2Ax=1%2B19\"Add \"19\" to both sides
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\n" ); document.write( " \"5%2Ax%2B5%2Ax=20\" Combine the terms on the right side
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\n" ); document.write( " \"10%2Ax=20\" Now combine the terms on the left side.
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\n" ); document.write( " \"cross%28%281%2F10%29%2810%2F1%29%29x=%2820%2F1%29%281%2F10%29\" Multiply both sides by \"1%2F10\". This will cancel out \"10%2F1\" and isolate x
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\n" ); document.write( " So when we multiply \"20%2F1\" and \"1%2F10\" (and simplify) we get
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\n" ); document.write( " \"x=2\" <---------------------------------One answer
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\n" ); document.write( " Now that we know that \"x=2\", lets substitute that in for x to solve for y
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\n" ); document.write( " \"5%282%29-3%2Ay=1\" Plug in \"x=2\" into the 2nd equation
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\n" ); document.write( " \"10-3%2Ay=1\" Multiply
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\n" ); document.write( " \"-3%2Ay=1-10\"Subtract \"10\" from both sides
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\n" ); document.write( " \"-3%2Ay=-9\" Combine the terms on the right side
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\n" ); document.write( " \"cross%28%281%2F-3%29%28-3%29%29%2Ay=%28-9%2F1%29%281%2F-3%29\" Multiply both sides by \"1%2F-3\". This will cancel out -3 on the left side.
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\n" ); document.write( " \"y=-9%2F-3\" Multiply the terms on the right side
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\n" ); document.write( " \"y=3\" Reduce
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\n" ); document.write( " So this is the other answer
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\n" ); document.write( " \"y=3\"<---------------------------------Other answer
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\n" ); document.write( " So our solution is
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\n" ); document.write( " \"x=2\" and \"y=3\"
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\n" ); document.write( " which can also look like
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\n" ); document.write( " (\"2\",\"3\")
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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( " \"5%2Ax%2B3%2Ay=19\"
\n" ); document.write( " \"5%2Ax-3%2Ay=1\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"5%2Ax%2B3%2Ay=19\" (red) and \"5%2Ax-3%2Ay=1\" (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 (\"2\",\"3\"). This verifies our answer.
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\n" ); document.write( " Plug in (\"2\",\"3\") into the system of equations
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\n" ); document.write( " Let \"x=2\" and \"y=3\". Now plug those values into the equation \"5%2Ax%2B3%2Ay=19\"
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\n" ); document.write( " \"5%2A%282%29%2B3%2A%283%29=19\" Plug in \"x=2\" and \"y=3\"
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\n" ); document.write( " \"10%2B9=19\" Multiply
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\n" ); document.write( " \"19=19\" Add
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\n" ); document.write( " \"19=19\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"2\",\"3\") satisfies \"5%2Ax%2B3%2Ay=19\"
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\n" ); document.write( " Let \"x=2\" and \"y=3\". Now plug those values into the equation \"5%2Ax-3%2Ay=1\"
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\n" ); document.write( " \"5%2A%282%29-3%2A%283%29=1\" Plug in \"x=2\" and \"y=3\"
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\n" ); document.write( " \"10-9=1\" Multiply
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\n" ); document.write( " \"1=1\" Add
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\n" ); document.write( " \"1=1\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"2\",\"3\") satisfies \"5%2Ax-3%2Ay=1\"
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\n" ); document.write( " Since the solution (\"2\",\"3\") satisfies the system of equations
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\n" ); document.write( " \"5%2Ax%2B3%2Ay=19\"
\n" ); document.write( " \"5%2Ax-3%2Ay=1\"
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\n" ); document.write( " this verifies our answer.
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