document.write( "Question 102664This question is from textbook
\n" ); document.write( ": Please help!\r
\n" ); document.write( "\n" ); document.write( "The problem is:\r
\n" ); document.write( "\n" ); document.write( "Solve the system by using the substitute method. Determine whether the equations are independent, dependent or inconsistent.\r
\n" ); document.write( "\n" ); document.write( "Eq 1 states: 3x + 5y = 25
\n" ); document.write( "Eq 2 states: x -2y = -10
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Algebra.Com's Answer #74680 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( " \"3%2Ax%2B5%2Ay=25\"
\n" ); document.write( " \"1%2Ax-2%2Ay=-10\"
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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=25-3%2Ax\"Subtract \"3%2Ax\" from both sides
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\n" ); document.write( " \"y=%2825-3%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=5-%283%2F5%29%2Ax\" Now we've fully isolated y
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\n" ); document.write( " Since y equals \"5-%283%2F5%29%2Ax\" we can substitute the expression \"5-%283%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( " \"1%2Ax%2B-2%2Ahighlight%28%285-%283%2F5%29%2Ax%29%29=-10\" Replace y with \"5-%283%2F5%29%2Ax\". Since this eliminates y, we can now solve for x.
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\n" ); document.write( " \"1%2Ax-2%2A%285%29-2%28-3%2F5%29x=-10\" Distribute -2 to \"5-%283%2F5%29%2Ax\"
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\n" ); document.write( " \"1%2Ax-10%2B%286%2F5%29%2Ax=-10\" Multiply
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\n" ); document.write( " \"1%2Ax-10%2B%286%2F5%29%2Ax=-10\" Reduce any fractions
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\n" ); document.write( " \"1%2Ax%2B%286%2F5%29%2Ax=-10%2B10\"Add \"10\" to both sides
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\n" ); document.write( " \"1%2Ax%2B%286%2F5%29%2Ax=0\" Combine the terms on the right side
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\n" ); document.write( " \"%285%2F5%29%2Ax%2B%286%2F5%29x=0\" Make 1 into a fraction with a denominator of 5
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\n" ); document.write( " \"%2811%2F5%29%2Ax=0\" Now combine the terms on the left side.
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\n" ); document.write( " \"cross%28%285%2F11%29%2811%2F5%29%29x=%280%2F1%29%285%2F11%29\" Multiply both sides by \"5%2F11\". This will cancel out \"11%2F5\" and isolate x
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\n" ); document.write( " So when we multiply \"0%2F1\" and \"5%2F11\" (and simplify) we get
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\n" ); document.write( " \"x=0\" <---------------------------------One answer
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\n" ); document.write( " Now that we know that \"x=0\", lets substitute that in for x to solve for y
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\n" ); document.write( " \"1%280%29-2%2Ay=-10\" Plug in \"x=0\" into the 2nd equation
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\n" ); document.write( " \"0-2%2Ay=-10\" Multiply
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\n" ); document.write( " \"-2%2Ay=-10%2B0\"Add \"0\" to both sides
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\n" ); document.write( " \"-2%2Ay=-10\" Combine the terms on the right side
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\n" ); document.write( " \"cross%28%281%2F-2%29%28-2%29%29%2Ay=%28-10%2F1%29%281%2F-2%29\" Multiply both sides by \"1%2F-2\". This will cancel out -2 on the left side.
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\n" ); document.write( " \"y=-10%2F-2\" 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=0\" and \"y=5\"
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\n" ); document.write( " which can also look like
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\n" ); document.write( " (\"0\",\"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%2B5%2Ay=25\"
\n" ); document.write( " \"1%2Ax-2%2Ay=-10\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"3%2Ax%2B5%2Ay=25\" (red) and \"1%2Ax-2%2Ay=-10\" (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 (\"0\",\"5\"). This verifies our answer.
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\n" ); document.write( " Check:
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\n" ); document.write( " Plug in (\"0\",\"5\") into the system of equations
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\n" ); document.write( " Let \"x=0\" and \"y=5\". Now plug those values into the equation \"3%2Ax%2B5%2Ay=25\"
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\n" ); document.write( " \"3%2A%280%29%2B5%2A%285%29=25\" Plug in \"x=0\" and \"y=5\"
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\n" ); document.write( " \"0%2B25=25\" Multiply
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\n" ); document.write( " \"25=25\" Add
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\n" ); document.write( " \"25=25\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"0\",\"5\") satisfies \"3%2Ax%2B5%2Ay=25\"
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\n" ); document.write( "
\n" ); document.write( " Let \"x=0\" and \"y=5\". Now plug those values into the equation \"1%2Ax-2%2Ay=-10\"
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\n" ); document.write( " \"1%2A%280%29-2%2A%285%29=-10\" Plug in \"x=0\" and \"y=5\"
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\n" ); document.write( " \"0-10=-10\" Multiply
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\n" ); document.write( " \"-10=-10\" Add
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\n" ); document.write( " \"-10=-10\" Reduce. Since this equation is true the solution works.
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\n" ); document.write( " So the solution (\"0\",\"5\") satisfies \"1%2Ax-2%2Ay=-10\"
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\n" ); document.write( " Since the solution (\"0\",\"5\") satisfies the system of equations
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\n" ); document.write( " \"3%2Ax%2B5%2Ay=25\"
\n" ); document.write( " \"1%2Ax-2%2Ay=-10\"
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\n" ); document.write( " this verifies our answer.
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