document.write( "Question 1130656: Solve the system using any method. (Simplify your answer completely. If the system is dependent, enter a general solution in terms of x and y. If there is no solution, enter NO SOLUTION.)\r
\n" ); document.write( "\n" ); document.write( "4x + 5y = 2
\n" ); document.write( "16x − 15y = 1
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Algebra.Com's Answer #747283 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "\"4x+%2B+5y+=+2\"
\n" ); document.write( "\"16x+-15y+=+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( " \"4%2Ax%2B5%2Ay=2\"
\n" ); document.write( " \"16%2Ax-15%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( " \"5%2Ay=2-4%2Ax\"Subtract \"4%2Ax\" from both sides
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\n" ); document.write( " \"y=%282-4%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=2%2F5-%284%2F5%29%2Ax\" Now we've fully isolated y
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\n" ); document.write( " Since y equals \"2%2F5-%284%2F5%29%2Ax\" we can substitute the expression \"2%2F5-%284%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( " \"16%2Ax%2B-15%2Ahighlight%28%282%2F5-%284%2F5%29%2Ax%29%29=1\" Replace y with \"2%2F5-%284%2F5%29%2Ax\". Since this eliminates y, we can now solve for x.
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\n" ); document.write( " \"16%2Ax-15%2A%282%2F5%29-15%28-4%2F5%29x=1\" Distribute -15 to \"2%2F5-%284%2F5%29%2Ax\"
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\n" ); document.write( " \"16%2Ax-30%2F5%2B%2860%2F5%29%2Ax=1\" Multiply
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\n" ); document.write( " \"16%2Ax-6%2B12%2Ax=1\" Reduce any fractions
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\n" ); document.write( " \"16%2Ax%2B12%2Ax=1%2B6\"Add \"6\" to both sides
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\n" ); document.write( " \"16%2Ax%2B12%2Ax=7\" Combine the terms on the right side
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\n" ); document.write( " \"28%2Ax=7\" Now combine the terms on the left side.
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\n" ); document.write( " \"cross%28%281%2F28%29%2828%2F1%29%29x=%287%2F1%29%281%2F28%29\" Multiply both sides by \"1%2F28\". This will cancel out \"28%2F1\" and isolate x
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\n" ); document.write( " So when we multiply \"7%2F1\" and \"1%2F28\" (and simplify) we get
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\n" ); document.write( " \"x=1%2F4\" <---------------------------------One answer
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\n" ); document.write( " Now that we know that \"x=1%2F4\", lets substitute that in for x to solve for y
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\n" ); document.write( " \"16%281%2F4%29-15%2Ay=1\" Plug in \"x=1%2F4\" into the 2nd equation
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\n" ); document.write( " \"4-15%2Ay=1\" Multiply
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\n" ); document.write( " \"-15%2Ay=1-4\"Subtract \"4\" from both sides
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\n" ); document.write( " \"-15%2Ay=-3\" Combine the terms on the right side
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\n" ); document.write( " \"cross%28%281%2F-15%29%28-15%29%29%2Ay=%28-3%2F1%29%281%2F-15%29\" Multiply both sides by \"1%2F-15\". This will cancel out -15 on the left side.
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\n" ); document.write( " \"y=-3%2F-15\" Multiply the terms on the right side
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\n" ); document.write( " \"y=1%2F5\" Reduce
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\n" ); document.write( " So this is the other answer
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\n" ); document.write( " \"y=1%2F5\"<---------------------------------Other answer
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\n" ); document.write( " So our solution is
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\n" ); document.write( " \"x=1%2F4\" and \"y=1%2F5\"
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\n" ); document.write( " which can also look like
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\n" ); document.write( " (\"1%2F4\",\"1%2F5\")
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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%2B5%2Ay=2\"
\n" ); document.write( " \"16%2Ax-15%2Ay=1\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"4%2Ax%2B5%2Ay=2\" (red) and \"16%2Ax-15%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 (\"1%2F4\",\"1%2F5\"). This verifies our answer.
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\n" ); document.write( " Check:
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\n" ); document.write( " Plug in (\"1%2F4\",\"1%2F5\") into the system of equations
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\n" ); document.write( " Let \"x=1%2F4\" and \"y=1%2F5\". Now plug those values into the equation \"4%2Ax%2B5%2Ay=2\"
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\n" ); document.write( " \"4%2A%281%2F4%29%2B5%2A%281%2F5%29=2\" Plug in \"x=1%2F4\" and \"y=1%2F5\"
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\n" ); document.write( " \"4%2F4%2B5%2F5=2\" Multiply
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\n" ); document.write( " \"40%2F20=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 (\"1%2F4\",\"1%2F5\") satisfies \"4%2Ax%2B5%2Ay=2\"
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\n" ); document.write( " Let \"x=1%2F4\" and \"y=1%2F5\". Now plug those values into the equation \"16%2Ax-15%2Ay=1\"
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\n" ); document.write( " \"16%2A%281%2F4%29-15%2A%281%2F5%29=1\" Plug in \"x=1%2F4\" and \"y=1%2F5\"
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\n" ); document.write( " \"16%2F4-15%2F5=1\" Multiply
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\n" ); document.write( " \"20%2F20=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 (\"1%2F4\",\"1%2F5\") satisfies \"16%2Ax-15%2Ay=1\"
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\n" ); document.write( " Since the solution (\"1%2F4\",\"1%2F5\") satisfies the system of equations
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\n" ); document.write( " \"4%2Ax%2B5%2Ay=2\"
\n" ); document.write( " \"16%2Ax-15%2Ay=1\"
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\n" ); document.write( " this verifies our answer.
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