document.write( "Question 938290: I'm not sure how to solve the following:
\n" ); document.write( "Solve the system by substitution.\r
\n" ); document.write( "\n" ); document.write( "y=6x-11
\n" ); document.write( "-2x-3y=-7
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Algebra.Com's Answer #571565 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
\"y=6x-11\"
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\n" ); document.write( "\n" ); document.write( "\"-6x%2By=-11\"
\n" ); document.write( "\"-2x-3y=-7\"
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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( " \"-6%2Ax%2B1%2Ay=-11\"
\n" ); document.write( " \"-2%2Ax-3%2Ay=-7\"
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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=-11%2B6%2Ax\"Add \"6%2Ax\" to both sides
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\n" ); document.write( " \"y=%28-11%2B6%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=-11%2B6%2Ax\" Now we've fully isolated y
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\n" ); document.write( " Since y equals \"-11%2B6%2Ax\" we can substitute the expression \"-11%2B6%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-3%2Ahighlight%28%28-11%2B6%2Ax%29%29=-7\" Replace y with \"-11%2B6%2Ax\". Since this eliminates y, we can now solve for x.
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\n" ); document.write( " \"-2%2Ax-3%2A%28-11%29-3%286%29x=-7\" Distribute -3 to \"-11%2B6%2Ax\"
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\n" ); document.write( " \"-2%2Ax%2B33-18%2Ax=-7\" Multiply
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\n" ); document.write( " \"-2%2Ax%2B33-18%2Ax=-7\" Reduce any fractions
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\n" ); document.write( " \"-2%2Ax-18%2Ax=-7-33\" Subtract \"33\" from both sides
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\n" ); document.write( " \"-2%2Ax-18%2Ax=-40\" Combine the terms on the right side
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\n" ); document.write( " \"-20%2Ax=-40\" Now combine the terms on the left side.
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\n" ); document.write( " \"cross%28%281%2F-20%29%28-20%2F1%29%29x=%28-40%2F1%29%281%2F-20%29\" Multiply both sides by \"1%2F-20\". This will cancel out \"-20%2F1\" and isolate x
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\n" ); document.write( " So when we multiply \"-40%2F1\" and \"1%2F-20\" (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( " \"-2%282%29-3%2Ay=-7\" Plug in \"x=2\" into the 2nd equation
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\n" ); document.write( " \"-4-3%2Ay=-7\" Multiply
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\n" ); document.write( " \"-3%2Ay=-7%2B4\"Add \"4\" to both sides
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\n" ); document.write( " \"-3%2Ay=-3\" 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=%28-3%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=-3%2F-3\" 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=2\" and \"y=1\"
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\n" ); document.write( " which can also look like
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\n" ); document.write( " (\"2\",\"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( " \"-6%2Ax%2B1%2Ay=-11\"
\n" ); document.write( " \"-2%2Ax-3%2Ay=-7\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"-6%2Ax%2B1%2Ay=-11\" (red) and \"-2%2Ax-3%2Ay=-7\" (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\",\"1\"). This verifies our answer.
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\n" ); document.write( " Check:
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\n" ); document.write( " Plug in (\"2\",\"1\") into the system of equations
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\n" ); document.write( " Let \"x=2\" and \"y=1\". Now plug those values into the equation \"-6%2Ax%2B1%2Ay=-11\"
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\n" ); document.write( " \"-6%2A%282%29%2B1%2A%281%29=-11\" Plug in \"x=2\" and \"y=1\"
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\n" ); document.write( " \"-12%2B1=-11\" Multiply
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\n" ); document.write( " \"-11=-11\" Add
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\n" ); document.write( " \"-11=-11\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"2\",\"1\") satisfies \"-6%2Ax%2B1%2Ay=-11\"
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\n" ); document.write( " Let \"x=2\" and \"y=1\". Now plug those values into the equation \"-2%2Ax-3%2Ay=-7\"
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\n" ); document.write( " \"-2%2A%282%29-3%2A%281%29=-7\" Plug in \"x=2\" and \"y=1\"
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\n" ); document.write( " \"-4-3=-7\" Multiply
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\n" ); document.write( " \"-7=-7\" Add
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\n" ); document.write( " \"-7=-7\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"2\",\"1\") satisfies \"-2%2Ax-3%2Ay=-7\"
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\n" ); document.write( " Since the solution (\"2\",\"1\") satisfies the system of equations
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\n" ); document.write( " \"-6%2Ax%2B1%2Ay=-11\"
\n" ); document.write( " \"-2%2Ax-3%2Ay=-7\"
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\n" ); document.write( " this verifies our answer.
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