document.write( "Question 119961: 4x+3y=-22
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Algebra.Com's Answer #87903 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( " \"4%2Ax%2B3%2Ay=-22\"
\n" ); document.write( " \"1%2Ax-3%2Ay=2\"
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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=-22-4%2Ax\"Subtract \"4%2Ax\" from both sides
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\n" ); document.write( " \"y=%28-22-4%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=-22%2F3-%284%2F3%29%2Ax\" Now we've fully isolated y
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\n" ); document.write( " Since y equals \"-22%2F3-%284%2F3%29%2Ax\" we can substitute the expression \"-22%2F3-%284%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( " \"1%2Ax%2B-3%2Ahighlight%28%28-22%2F3-%284%2F3%29%2Ax%29%29=2\" Replace y with \"-22%2F3-%284%2F3%29%2Ax\". Since this eliminates y, we can now solve for x.
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\n" ); document.write( " \"1%2Ax-3%2A%28-22%2F3%29-3%28-4%2F3%29x=2\" Distribute -3 to \"-22%2F3-%284%2F3%29%2Ax\"
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\n" ); document.write( " \"1%2Ax%2B66%2F3%2B%2812%2F3%29%2Ax=2\" Multiply
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\n" ); document.write( " \"1%2Ax%2B22%2B4%2Ax=2\" Reduce any fractions
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\n" ); document.write( " \"1%2Ax%2B4%2Ax=2-22\" Subtract \"22\" from both sides
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\n" ); document.write( " \"1%2Ax%2B4%2Ax=-20\" Combine the terms on the right side
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\n" ); document.write( " \"5%2Ax=-20\" Now combine the terms on the left side.
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\n" ); document.write( " \"cross%28%281%2F5%29%285%2F1%29%29x=%28-20%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 \"-20%2F1\" and \"1%2F5\" (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( " \"1%28-4%29-3%2Ay=2\" Plug in \"x=-4\" into the 2nd equation
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\n" ); document.write( " \"-4-3%2Ay=2\" Multiply
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\n" ); document.write( " \"-3%2Ay=2%2B4\"Add \"4\" to both sides
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\n" ); document.write( " \"-3%2Ay=6\" 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=%286%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=6%2F-3\" Multiply the terms on the right side
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\n" ); document.write( " \"y=-2\" Reduce
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\n" ); document.write( " So this is the other answer
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\n" ); document.write( " \"y=-2\"<---------------------------------Other answer
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\n" ); document.write( " So our solution is
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\n" ); document.write( " \"x=-4\" and \"y=-2\"
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\n" ); document.write( " which can also look like
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\n" ); document.write( " (\"-4\",\"-2\")
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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( " \"4%2Ax%2B3%2Ay=-22\"
\n" ); document.write( " \"1%2Ax-3%2Ay=2\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"4%2Ax%2B3%2Ay=-22\" (red) and \"1%2Ax-3%2Ay=2\" (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\",\"-2\"). This verifies our answer.
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\n" ); document.write( " Check:
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\n" ); document.write( " Plug in (\"-4\",\"-2\") into the system of equations
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\n" ); document.write( " Let \"x=-4\" and \"y=-2\". Now plug those values into the equation \"4%2Ax%2B3%2Ay=-22\"
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\n" ); document.write( " \"4%2A%28-4%29%2B3%2A%28-2%29=-22\" Plug in \"x=-4\" and \"y=-2\"
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\n" ); document.write( " \"-16-6=-22\" Multiply
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\n" ); document.write( " \"-22=-22\" Add
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\n" ); document.write( " \"-22=-22\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"-4\",\"-2\") satisfies \"4%2Ax%2B3%2Ay=-22\"
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\n" ); document.write( " Let \"x=-4\" and \"y=-2\". Now plug those values into the equation \"1%2Ax-3%2Ay=2\"
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\n" ); document.write( " \"1%2A%28-4%29-3%2A%28-2%29=2\" Plug in \"x=-4\" and \"y=-2\"
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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\",\"-2\") satisfies \"1%2Ax-3%2Ay=2\"
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\n" ); document.write( " Since the solution (\"-4\",\"-2\") satisfies the system of equations
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\n" ); document.write( " \"4%2Ax%2B3%2Ay=-22\"
\n" ); document.write( " \"1%2Ax-3%2Ay=2\"
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\n" ); document.write( " this verifies our answer.
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