document.write( "Question 99730: O is the midpoint of NP; NP = 3x + 4y , NO = 2x + 3y - 5, OP = 5x - y, FIND the lengths of NO,OP, and NP. May you please show work also.\r
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Algebra.Com's Answer #72603 by edjones(8007)\"\" \"About 
You can put this solution on YOUR website!
A) 2x+3y-5=5x-y
\n" ); document.write( "subtract 5x and add y to each side: -3x+4y-5=0
\n" ); document.write( "add 5 to each side: -3x+4y=5
\n" ); document.write( "B) 3x+4y=2(2x+3y-5)
\n" ); document.write( "3x+4y=4x+6y-10
\n" ); document.write( "subtract 4 and 6y from each side: -x-2y=-10
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Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition

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\n" ); document.write( " Lets start with the given system of linear equations
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\n" ); document.write( " \"-1%2Ax-2%2Ay=-10\"
\n" ); document.write( " \"-3%2Ax%2B4%2Ay=5\"
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\n" ); document.write( " In order to solve for one variable, we must eliminate the other variable. So if we wanted to solve for y, we would have to eliminate x (or vice versa).
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\n" ); document.write( " So lets eliminate x. In order to do that, we need to have both x coefficients that are equal but have opposite signs (for instance 2 and -2 are equal but have opposite signs). This way they will add to zero.
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\n" ); document.write( " So to make the x coefficients equal but opposite, we need to multiply both x coefficients by some number to get them to an equal number. So if we wanted to get -1 and -3 to some equal number, we could try to get them to the LCM.
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\n" ); document.write( " Since the LCM of -1 and -3 is 3, we need to multiply both sides of the top equation by -3 and multiply both sides of the bottom equation by 1 like this:
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\n" ); document.write( " \"-3%2A%28-1%2Ax-2%2Ay%29=%28-10%29%2A-3\" Multiply the top equation (both sides) by -3
\n" ); document.write( " \"1%2A%28-3%2Ax%2B4%2Ay%29=%285%29%2A1\" Multiply the bottom equation (both sides) by 1
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\n" ); document.write( " So after multiplying we get this:
\n" ); document.write( " \"3%2Ax%2B6%2Ay=30\"
\n" ); document.write( " \"-3%2Ax%2B4%2Ay=5\"
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\n" ); document.write( " Notice how 3 and -3 add to zero (ie \"3%2B-3=0\")
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\n" ); document.write( " Now add the equations together. In order to add 2 equations, group like terms and combine them
\n" ); document.write( " \"%283%2Ax-3%2Ax%29%2B%286%2Ay%2B4%2Ay%29=30%2B5\"
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\n" ); document.write( " \"%283-3%29%2Ax%2B%286%2B4%29y=30%2B5\"
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\n" ); document.write( " \"cross%283%2B-3%29%2Ax%2B%286%2B4%29%2Ay=30%2B5\" Notice the x coefficients add to zero and cancel out. This means we've eliminated x altogether.
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\n" ); document.write( " So after adding and canceling out the x terms we're left with:
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\n" ); document.write( " \"10%2Ay=35\"
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\n" ); document.write( " \"y=35%2F10\" Divide both sides by \"10\" to solve for y
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\n" ); document.write( " \"y=7%2F2\" Reduce
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\n" ); document.write( " Now plug this answer into the top equation \"-1%2Ax-2%2Ay=-10\" to solve for x
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\n" ); document.write( " \"-1%2Ax-2%287%2F2%29=-10\" Plug in \"y=7%2F2\"
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\n" ); document.write( " \"-1%2Ax-14%2F2=-10\" Multiply
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\n" ); document.write( " \"-1%2Ax-7=-10\" Reduce
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\n" ); document.write( " \"-1%2Ax=-10%2B7\" Subtract \"-7\" from both sides
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\n" ); document.write( " \"-1%2Ax=-3\" Combine the terms on the right side
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\n" ); document.write( " \"cross%28%281%2F-1%29%28-1%29%29%2Ax=%28-3%29%281%2F-1%29\" Multiply both sides by \"1%2F-1\". This will cancel out \"-1\" on the left side.
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\n" ); document.write( " \"x=3\" Multiply the terms on the right side
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\n" ); document.write( " So our answer is
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\n" ); document.write( " \"x=3\", \"y=7%2F2\"
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\n" ); document.write( " which also looks like
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\n" ); document.write( " (\"3\", \"7%2F2\")
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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( " \"-1%2Ax-2%2Ay=-10\"
\n" ); document.write( " \"-3%2Ax%2B4%2Ay=5\"
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\n" ); document.write( " we get
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\n" ); document.write( " graph of \"-1%2Ax-2%2Ay=-10\" (red) \"-3%2Ax%2B4%2Ay=5\" (green) (hint: you may have to solve for y to graph these) and the intersection of the lines (blue circle).
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\n" ); document.write( " and we can see that the two equations intersect at (\"3\",\"7%2F2\"). This verifies our answer.

\n" ); document.write( "\n" ); document.write( "Check:
\n" ); document.write( "NO) 6+10.5-5=11.5
\n" ); document.write( "OP) 15-3.5=11.5
\n" ); document.write( "NP) 9+14=23
\n" ); document.write( "11.5+11.5=23
\n" ); document.write( "Ed
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