document.write( "Question 152808: solve the system:\r
\n" ); document.write( "\n" ); document.write( "x+3y+5z=20
\n" ); document.write( "y-4z=-16
\n" ); document.write( "3x-2y+9z=36
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Algebra.Com's Answer #112899 by Electrified_Levi(103)\"\" \"About 
You can put this solution on YOUR website!
Hi, Hope I can help,
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\n" ); document.write( "solve the system:
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\n" ); document.write( "x+3y+5z=20
\n" ); document.write( "y-4z=(-16)
\n" ); document.write( "3x-2y+9z=36
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\n" ); document.write( "This is the way I usually solve these problems(pretty easy once you know how to do it) ( There is no fast way to solve these problems)
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\n" ); document.write( "First, solve for a letter in all the equations( since we already have a 2 system/variable equation for equation 2, we don't have to solve for any letter in equation 2)( Since \"+y+-+4z+=+%28-16%29+\" that means we will need to solve for \"x\" in our other equations)
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\n" ); document.write( "We will rewrite the 3 equations so it makes more sense( the second equation has no \"x's\" in the equation so it has \"0x\")
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\n" ); document.write( "x+3y+5z=20
\n" ); document.write( "0x + y - 4z =( -16)
\n" ); document.write( "3x-2y+9z=36
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\n" ); document.write( "We will switch the equations around
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\n" ); document.write( "x+3y+5z=20
\n" ); document.write( "3x-2y+9z=36
\n" ); document.write( "0x + y - 4z = (-16)
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\n" ); document.write( "We will solve \"x\" in our first two equations(can't solve \"x\" in our third equation, since it is 0x)
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\n" ); document.write( "First equation
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\n" ); document.write( "\"+x%2B3y%2B5z=20+\"
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\n" ); document.write( "We will move \"3y\" over to the right side
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\n" ); document.write( "\"+x%2B3y%2B5z=20+\" = \"+x%2B3y+-+3y+%2B5z=20+-3y+\"
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\n" ); document.write( "\"+x%2B3y+-+3y+%2B5z=20+-3y+\" = \"+x+%2B+5z=+20+-+3y+\"
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\n" ); document.write( "We will move \"5z\" to the right side
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\n" ); document.write( "\"+x+%2B+5z=+20+-+3y+\" = \"+x+%2B+5z+-+5z+=+20+-+3y+-+5z+\"
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\n" ); document.write( "\"+x+%2B+5z+-+5z+=+20+-+3y+-+5z+\" = \"+x+=+20+-+3y+-+5z+\"
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\n" ); document.write( "We will switch the letters around
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\n" ); document.write( "\"+x+=+20+-+3y+-+5z+\" = \"+x+=+%28-3y%29+-+5z+%2B+20+\"
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\n" ); document.write( "This is our First Answer \"+%28-3y%29+-+5z+%2B+20+\"
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\n" ); document.write( "We will now solve \"x\" in our second equation
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\n" ); document.write( "\"+3x-2y%2B9z=36+\"
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\n" ); document.write( "We will move (-2y) to the right side
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\n" ); document.write( "\"+3x-2y%2B9z=36+\" = \"+3x-2y+%2B+2y+%2B9z=36+%2B+2y+\"
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\n" ); document.write( "\"+3x-2y+%2B+2y+%2B9z=36+%2B+2y+\" = \"+3x+%2B+9z+=+36+%2B+2y+\"
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\n" ); document.write( "We will move \"9z\" to the right side
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\n" ); document.write( "\"+3x+%2B+9z+=+36+%2B+2y+\" = \"+3x+%2B+9z+-+9z+=+36+%2B+2y+-+9z+\"
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\n" ); document.write( "\"+3x+%2B+9z+-+9z+=+36+%2B+2y+-+9z+\" = \"+3x+=+36+%2B+2y+-+9z+\"
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\n" ); document.write( "We will switch the letters around
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\n" ); document.write( "\"+3x+=+36+%2B+2y+-+9z+\" = \"+3x+=+2y+-+9z+%2B+36+\"
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\n" ); document.write( "We will now divide each side by \"3\"
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\n" ); document.write( "\"+3x+=+2y+-+9z+%2B+36+\" = \"+3x%2F3+=+%282y+-+9z+%2B+36%29%2F3+\"
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\n" ); document.write( "\"+3x%2F3+=+%282y+-+9z+%2B+36%29%2F3+\" = \"+cross+%283%29x%2Fcross%283%29+=+%282y+-+9z+%2B+36%29%2F3+\"
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\n" ); document.write( "\"+x+=+%282y+-+9z+%2B+36%29%2F3+\"
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\n" ); document.write( "Our second answer = \"+%282y+-+9z+%2B+36%29%2F3+\"
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\n" ); document.write( "We can now solve to get a 2 system(variable) equation
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\n" ); document.write( "We will put our two answers together in an equation, since \"x\" = both of the answers, our answers equal each other
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\n" ); document.write( "First answer = \"+%28-3y%29+-+5z+%2B+20+\"
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\n" ); document.write( "Second answer = \"+%282y+-+9z+%2B+36%29%2F3+\"
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\n" ); document.write( "Our equation will equal \"+%28-3y%29+-+5z+%2B+20+=+%282y+-+9z+%2B+36%29%2F3+\"
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\n" ); document.write( "\"+%28-3y%29+-+5z+%2B+20+=+%282y+-+9z+%2B+36%29%2F3+\" = \"+%28%28-3y%29+-+5z+%2B+20%29%2F1+=+%282y+-+9z+%2B+36%29%2F3+\"
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\n" ); document.write( "We will use cross multiplication to get rid of the fractions
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\n" ); document.write( "\"+highlight%28%28-3y%29+-+5z+%2B+20%29%2F1+=+%282y+-+9z+%2B+36%29%2F+highlight%283%29+\"
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\n" ); document.write( "\"+%28-9y%29+-+15z+%2B+60+=+2y+-+9z+%2B+36+\"
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\n" ); document.write( "We will move (-9y) to the right side
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\n" ); document.write( "\"+%28-9y%29+%2B+9y+-+15z+%2B+60+=+2y+%2B+9y+-+9z+%2B+36+\"
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\n" ); document.write( "\"+%28-9y%29+%2B+9y+-+15z+%2B+60+=+2y+%2B+9y+-+9z+%2B+36+\" = \"+%28-15z%29+%2B+60+=+11y+-+9z+%2B+36+\"
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\n" ); document.write( "We will move the (-15z) to the right side
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\n" ); document.write( "\"+%28-15z%29+%2B+60+=+11y+-+9z+%2B+36+\" = \"+%28-15z%29+%2B+15z+%2B+60+=+11y+-+9z+%2B+15z+%2B+36+\"
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\n" ); document.write( "\"+%28-15z%29+%2B+15z+%2B+60+=+11y+-+9z+%2B+15z+%2B+36+\" = \"+60+=+11y+%2B+6z+%2B+36+\"
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\n" ); document.write( "We will move the \"36\" to the left side
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\n" ); document.write( "\"+60+=+11y+%2B+6z+%2B+36+\" = \"+60+-+36+=+11y+%2B+6z+%2B+36+-+36+\"
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\n" ); document.write( "\"+60+-+36+=+11y+%2B+6z+%2B+36+-+36+\" = \"+24+=+11y+%2B+6z+\"
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\n" ); document.write( "We will rearrange, \"+24+=+11y+%2B+6z+\" = \"+11y+%2B+6z+=+24+\"
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\n" ); document.write( "Our second 2 system/variable equation = \"+11y+%2B+6z+=+24+\"
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\n" ); document.write( "We will put our two 2 system/variable equations side by side
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\n" ); document.write( "First equation = \"+y-4z=%28-16%29+\"
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\n" ); document.write( "Second equation = \"+11y+%2B+6z+=+24+\"
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\n" ); document.write( "\"+y-4z=%28-16%29+\"
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\n" ); document.write( "\"+11y+%2B+6z+=+24+\"
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\n" ); document.write( "We will now need to solve for a letter again( we will solve \"y\" since it is the easiest to solve)
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\n" ); document.write( "First equation \"+y-4z=%28-16%29+\"
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\n" ); document.write( "We will move (-4z) to the right side
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\n" ); document.write( "\"+y-4z=%28-16%29+\" = \"+y-4z+%2B+4z+=%28-16%29+%2B+4z+\"
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\n" ); document.write( "\"+y-4z+%2B+4z+=%28-16%29+%2B+4z+\" = \"+y+=+%28-16%29+%2B+4z+\"
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\n" ); document.write( "\"+y+=+%28-16%29+%2B+4z+\" = \"+y+=+4z+-+16+\" ( rearranging the numbers)
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\n" ); document.write( "Our first answer = \"+4z+-+16+\"
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\n" ); document.write( "Our second equation \"+11y+%2B+6z+=+24+\"
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\n" ); document.write( "We will move \"6z\" to the right side
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\n" ); document.write( "\"+11y+%2B+6z+=+24+\" = \"+11y+%2B+6z+-+6z+=+24+-+6z+\"
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\n" ); document.write( "\"+11y+%2B+6z+-+6z+=+24+-+6z+\" = \"+11y+=+24+-+6z+\"
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\n" ); document.write( "Rearranging \"+11y+=+24+-+6z+\" = \"+11y+=++%28-6z%29+%2B+24+\"
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\n" ); document.write( "We will divide each side by \"11\"
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\n" ); document.write( "\"+11y+=++%28-6z%29+%2B+24+\" = \"+11y%2F11+=++%28%28-6z%29+%2B+24%29%2F11+\"
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\n" ); document.write( "\"+11y%2F11+=++%28%28-6z%29+%2B+24%29%2F11+\" = \"+cross+%2811%29y%2Fcross+%2811%29+=++%28%28-6z%29+%2B+24%29%2F11+\"
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\n" ); document.write( "\"+cross+%2811%29y%2Fcross+%2811%29+=++%28%28-6z%29+%2B+24%29%2F11+\" = \"+y+=++%28%28-6z%29+%2B+24%29%2F11+\"
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\n" ); document.write( "Our second answer is \"+%28%28-6z%29+%2B+24%29%2F11+\"
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\n" ); document.write( "We can now put both of our answers into an equation( since \"y\" equals both of our answers)
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\n" ); document.write( "Answer 1 = \"+4z+-+16+\"
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\n" ); document.write( "Answer 2 = \"+%28%28-6z%29+%2B+24%29%2F11+\"
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\n" ); document.write( "We can make our equation, it equals \"+4z+-+16+=+%28%28-6z%29+%2B+24%29%2F11+\"
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\n" ); document.write( "\"+4z+-+16+=+%28%28-6z%29+%2B+24%29%2F11+\" = \"+%284z+-+16%29%2F1+=+%28%28-6z%29+%2B+24%29%2F11+\"
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\n" ); document.write( "We will cross multiply to get rid of the fractions
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\n" ); document.write( "\"+highlight%284z+-+16%29%2F1+=+%28%28-6z%29+%2B+24%29%2Fhighlight%2811%29+\"
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\n" ); document.write( "It becomes, \"+44z+-+176+=+%28-6z%29+%2B+24+\"
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\n" ); document.write( "We will move (-6z) to the left side
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\n" ); document.write( "\"+44z+-+176+=+%28-6z%29+%2B+24+\" = \"+44z+%2B+6z+-+176+=+%28-6z%29+%2B+6z+%2B+24+\"
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\n" ); document.write( "\"+44z+%2B+6z+-+176+=+%28-6z%29+%2B+6z+%2B+24+\" = \"+50z+-+176+=+24+\"
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\n" ); document.write( "We will move (-176) to the right side
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\n" ); document.write( "\"+50z+-+176+=+24+\" = \"+50z+-+176+%2B+176+=+24+%2B+176+\"
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\n" ); document.write( "\"+50z+-+176+%2B+176+=+24+%2B+176+\" = \"+50z+=+200+\"
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\n" ); document.write( "We will divide each side by \"50\"
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\n" ); document.write( "\"+50z+=+200+\" = \"+50z%2F50+=+200%2F50+\"
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\n" ); document.write( "\"+50z%2F50+=+200%2F50+\" = \"+cross%2850%29z%2Fcross%2850%29+=+4+\"
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\n" ); document.write( "\"+cross%2850%29z%2Fcross%2850%29+=+4+\" = \"+z+=+4+\"
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\n" ); document.write( "We found that \"z\" = 4, we can replace \"z\" with \"4\" in one of our 2 system/variable equations
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\n" ); document.write( "\"+y-4z=%28-16%29+\"
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\n" ); document.write( "\"+11y+%2B+6z+=+24+\"
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\n" ); document.write( "We will use the first equation
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\n" ); document.write( "\"+y-4z=%28-16%29+\" = \"+y-4%284%29=%28-16%29+\"
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\n" ); document.write( "\"+y-4%284%29=%28-16%29+\" = \"+y+-+16+=+%28-16%29+\"
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\n" ); document.write( "We will move (-16) to the right
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\n" ); document.write( "\"+y+-+16+=+%28-16%29+\" = \"+y+-+16+%2B+16+=+%28-16%29+%2B+16+\"
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\n" ); document.write( "\"+y+-+16+%2B+16+=+%28-16%29+%2B+16+\" = \"+y+=+0+\"
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\n" ); document.write( "We found that \"y\" = \"0\"
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\n" ); document.write( "We can now find \"x\", we need to replace \"y\" and \"z\" in one of the three original equations
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\n" ); document.write( "y = 0
\n" ); document.write( "z = 4
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\n" ); document.write( "x+3y+5z=20
\n" ); document.write( "y-4z=(-16)
\n" ); document.write( "3x-2y+9z=36
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\n" ); document.write( "We will use the first equation, since it will be the easiest( we can't use the second equation)
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\n" ); document.write( "\"+x%2B3y%2B5z=20+\" = \"+x%2B3%280%29%2B5%284%29=20+\"
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\n" ); document.write( "\"+x%2B3%280%29%2B5%284%29=20+\" = \"+x%2B0%2B20=20+\"
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\n" ); document.write( "\"+x%2B0%2B20=20+\" = \"+x%2B20=20+\"
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\n" ); document.write( "We will move the \"20\" over to the right side
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\n" ); document.write( "\"+x%2B20=20+\" = \"+x%2B20-20=20+-+20+\"
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\n" ); document.write( "\"+x=0+\"
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\n" ); document.write( "We found that \"x\" = \"0\", we now have all 3 variables, \"x\",\"y\", and \"z\"
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\n" ); document.write( "x = 0
\n" ); document.write( "y = 0
\n" ); document.write( "z = 4
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\n" ); document.write( "We can check by replacing the letters with numbers in our third equation
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\n" ); document.write( "\"+3x-2y%2B9z=36+\" = \"+3%280%29-+2%280%29+%2B+9%284%29+=+36+\"
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\n" ); document.write( "\"+3%280%29-+2%280%29+%2B+9%284%29+=+36+\" = \"+0+-+0+%2B+36+=+36+\"
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\n" ); document.write( "\"+0+-+0+%2B+36+=+36+\" = \"+36+=+36+\" ( True)
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\n" ); document.write( "x = 0
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\n" ); document.write( "z = 4
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\n" ); document.write( "The solution set = (x,y,z), our solution set = (0,0,4)
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\n" ); document.write( "Hope I helped, Levi
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