document.write( "Question 698280: 6x+5y=150
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\n" ); document.write( "\n" ); document.write( "Explain to me how to do this, using the Substitution method
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Algebra.Com's Answer #430571 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
\"6x%2B5y=150\"
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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%2B5%2Ay=150\"
\n" ); document.write( " \"9%2Ax%2B10%2Ay=270\"
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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( " \"5%2Ay=150-6%2Ax\"Subtract \"6%2Ax\" from both sides
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\n" ); document.write( " \"y=%28150-6%2Ax%29%2F5\" Divide both sides by 5.
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\n" ); document.write( " Which breaks down and reduces to
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\n" ); document.write( " \"y=30-%286%2F5%29%2Ax\" Now we've fully isolated y
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\n" ); document.write( " Since y equals \"30-%286%2F5%29%2Ax\" we can substitute the expression \"30-%286%2F5%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( " \"9%2Ax%2B10%2Ahighlight%28%2830-%286%2F5%29%2Ax%29%29=270\" Replace y with \"30-%286%2F5%29%2Ax\". Since this eliminates y, we can now solve for x.
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\n" ); document.write( " \"9%2Ax%2B10%2A%2830%29%2B10%28-6%2F5%29x=270\" Distribute 10 to \"30-%286%2F5%29%2Ax\"
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\n" ); document.write( " \"9%2Ax%2B300-%2860%2F5%29%2Ax=270\" Multiply
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\n" ); document.write( " \"9%2Ax%2B300-12%2Ax=270\" Reduce any fractions
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\n" ); document.write( " \"9%2Ax-12%2Ax=270-300\" Subtract \"300\" from both sides
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\n" ); document.write( " \"9%2Ax-12%2Ax=-30\" Combine the terms on the right side
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\n" ); document.write( " \"-3%2Ax=-30\" Now combine the terms on the left side.
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\n" ); document.write( " \"cross%28%281%2F-3%29%28-3%2F1%29%29x=%28-30%2F1%29%281%2F-3%29\" Multiply both sides by \"1%2F-3\". This will cancel out \"-3%2F1\" and isolate x
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\n" ); document.write( " So when we multiply \"-30%2F1\" and \"1%2F-3\" (and simplify) we get
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\n" ); document.write( " \"x=10\" <---------------------------------One answer
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\n" ); document.write( " Now that we know that \"x=10\", lets substitute that in for x to solve for y
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\n" ); document.write( " \"9%2810%29%2B10%2Ay=270\" Plug in \"x=10\" into the 2nd equation
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\n" ); document.write( " \"90%2B10%2Ay=270\" Multiply
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\n" ); document.write( " \"10%2Ay=270-90\"Subtract \"90\" from both sides
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\n" ); document.write( " \"10%2Ay=180\" Combine the terms on the right side
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\n" ); document.write( " \"cross%28%281%2F10%29%2810%29%29%2Ay=%28180%2F1%29%281%2F10%29\" Multiply both sides by \"1%2F10\". This will cancel out 10 on the left side.
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\n" ); document.write( " \"y=180%2F10\" Multiply the terms on the right side
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\n" ); document.write( " \"y=18\" Reduce
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\n" ); document.write( " So this is the other answer
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\n" ); document.write( " \"y=18\"<---------------------------------Other answer
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\n" ); document.write( " So our solution is
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\n" ); document.write( " \"x=10\" and \"y=18\"
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\n" ); document.write( " which can also look like
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\n" ); document.write( " (\"10\",\"18\")
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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%2B5%2Ay=150\"
\n" ); document.write( " \"9%2Ax%2B10%2Ay=270\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"6%2Ax%2B5%2Ay=150\" (red) and \"9%2Ax%2B10%2Ay=270\" (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 (\"10\",\"18\"). This verifies our answer.
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\n" ); document.write( " Plug in (\"10\",\"18\") into the system of equations
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\n" ); document.write( " Let \"x=10\" and \"y=18\". Now plug those values into the equation \"6%2Ax%2B5%2Ay=150\"
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\n" ); document.write( " \"6%2A%2810%29%2B5%2A%2818%29=150\" Plug in \"x=10\" and \"y=18\"
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\n" ); document.write( " \"60%2B90=150\" Multiply
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\n" ); document.write( " \"150=150\" Add
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\n" ); document.write( " \"150=150\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"10\",\"18\") satisfies \"6%2Ax%2B5%2Ay=150\"
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\n" ); document.write( " Let \"x=10\" and \"y=18\". Now plug those values into the equation \"9%2Ax%2B10%2Ay=270\"
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\n" ); document.write( " \"9%2A%2810%29%2B10%2A%2818%29=270\" Plug in \"x=10\" and \"y=18\"
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\n" ); document.write( " \"90%2B180=270\" Multiply
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\n" ); document.write( " \"270=270\" Add
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\n" ); document.write( " \"270=270\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"10\",\"18\") satisfies \"9%2Ax%2B10%2Ay=270\"
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\n" ); document.write( " Since the solution (\"10\",\"18\") satisfies the system of equations
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\n" ); document.write( " \"6%2Ax%2B5%2Ay=150\"
\n" ); document.write( " \"9%2Ax%2B10%2Ay=270\"
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\n" ); document.write( " this verifies our answer.
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