document.write( "Question 403327: Y=3x+11
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\n" ); document.write( "I'm trying to solve this equtation using substitution
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Algebra.Com's Answer #285224 by MathLover1(20855)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "\"y=3x%2B11\"\r
\n" ); document.write( "\n" ); document.write( "\"y=-2x%2B1\".....write in standard form\r
\n" ); document.write( "\n" ); document.write( "\"-3x+%2B+y+=+11\"\r
\n" ); document.write( "\n" ); document.write( "\"2x+%2B+y+=+1\"\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( " \"-3%2Ax%2B1%2Ay=11\"
\n" ); document.write( " \"2%2Ax%2B1%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( " \"1%2Ay=11%2B3%2Ax\"Add \"3%2Ax\" to both sides
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\n" ); document.write( " \"y=%2811%2B3%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%2B3%2Ax\" Now we've fully isolated y
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\n" ); document.write( " Since y equals \"11%2B3%2Ax\" we can substitute the expression \"11%2B3%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%2B1%2Ahighlight%28%2811%2B3%2Ax%29%29=1\" Replace y with \"11%2B3%2Ax\". Since this eliminates y, we can now solve for x.
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\n" ); document.write( " \"2%2Ax%2B1%2A%2811%29%2B1%283%29x=1\" Distribute 1 to \"11%2B3%2Ax\"
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\n" ); document.write( " \"2%2Ax%2B11%2B3%2Ax=1\" Multiply
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\n" ); document.write( " \"2%2Ax%2B11%2B3%2Ax=1\" Reduce any fractions
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\n" ); document.write( " \"2%2Ax%2B3%2Ax=1-11\" Subtract \"11\" from both sides
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\n" ); document.write( " \"2%2Ax%2B3%2Ax=-10\" Combine the terms on the right side
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\n" ); document.write( " \"5%2Ax=-10\" Now combine the terms on the left side.
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\n" ); document.write( " \"cross%28%281%2F5%29%285%2F1%29%29x=%28-10%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 \"-10%2F1\" and \"1%2F5\" (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%28-2%29%2B1%2Ay=1\" Plug in \"x=-2\" into the 2nd equation
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\n" ); document.write( " \"-4%2B1%2Ay=1\" Multiply
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\n" ); document.write( " \"1%2Ay=1%2B4\"Add \"4\" to both sides
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\n" ); document.write( " \"1%2Ay=5\" Combine the terms on the right side
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\n" ); document.write( " \"cross%28%281%2F1%29%281%29%29%2Ay=%285%2F1%29%281%2F1%29\" Multiply both sides by \"1%2F1\". This will cancel out 1 on the left side.
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\n" ); document.write( " \"y=5%2F1\" Multiply the terms on the right side
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\n" ); document.write( " \"y=5\" Reduce
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\n" ); document.write( " So this is the other answer
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\n" ); document.write( " \"y=5\"<---------------------------------Other answer
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\n" ); document.write( " So our solution is
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\n" ); document.write( " \"x=-2\" and \"y=5\"
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\n" ); document.write( " which can also look like
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\n" ); document.write( " (\"-2\",\"5\")
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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=11\"
\n" ); document.write( " \"2%2Ax%2B1%2Ay=1\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"-3%2Ax%2B1%2Ay=11\" (red) and \"2%2Ax%2B1%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\",\"5\"). This verifies our answer.
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\n" ); document.write( " Check:
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\n" ); document.write( " Plug in (\"-2\",\"5\") into the system of equations
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\n" ); document.write( " Let \"x=-2\" and \"y=5\". Now plug those values into the equation \"-3%2Ax%2B1%2Ay=11\"
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\n" ); document.write( " \"-3%2A%28-2%29%2B1%2A%285%29=11\" Plug in \"x=-2\" and \"y=5\"
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\n" ); document.write( " \"6%2B5=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\",\"5\") satisfies \"-3%2Ax%2B1%2Ay=11\"
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\n" ); document.write( " Let \"x=-2\" and \"y=5\". Now plug those values into the equation \"2%2Ax%2B1%2Ay=1\"
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\n" ); document.write( " \"2%2A%28-2%29%2B1%2A%285%29=1\" Plug in \"x=-2\" and \"y=5\"
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\n" ); document.write( " \"-4%2B5=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\",\"5\") satisfies \"2%2Ax%2B1%2Ay=1\"
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\n" ); document.write( " Since the solution (\"-2\",\"5\") satisfies the system of equations
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\n" ); document.write( " \"-3%2Ax%2B1%2Ay=11\"
\n" ); document.write( " \"2%2Ax%2B1%2Ay=1\"
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\n" ); document.write( " this verifies our answer.
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