document.write( "Question 175229: System of equations\r
\n" ); document.write( "\n" ); document.write( "-4x+4y-2z=-8
\n" ); document.write( "-3x-y+4z=0
\n" ); document.write( "2x-2y+3z=-4\r
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\n" ); document.write( "\n" ); document.write( "I dont understand the steps to this i always come out with a diffrent answer then one of the choices. So if u could please help. Thanks \n" ); document.write( "
Algebra.Com's Answer #130327 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
System of equations
\n" ); document.write( "-4x+4y-2z=-8
\n" ); document.write( "-3x-y+4z=0
\n" ); document.write( "2x-2y+3z=-4
\n" ); document.write( ":
\n" ); document.write( "There are several ways to solve this, but this one lends itself to the elimination method.
\n" ); document.write( ":
\n" ); document.write( "Multiply the 3rd equation by 2 and and add to the 1st equation
\n" ); document.write( "-4x + 4y - 2z = -8
\n" ); document.write( "+4x - 4y + 6z = -8
\n" ); document.write( "---------------------addition eliminates x & y, easy to find z
\n" ); document.write( "0x + 0y + 4z = -16
\n" ); document.write( "z = \"%28-16%29%2F4\"
\n" ); document.write( "z = -4
\n" ); document.write( ":
\n" ); document.write( "Substitute -4 for z in the 2nd equation
\n" ); document.write( "-3x - y + 4(-4) = 0
\n" ); document.write( "-3x - y - 16 = 0
\n" ); document.write( "-3x - y = 16
\n" ); document.write( ":
\n" ); document.write( "Substitute -4 for z in the 3rd equation
\n" ); document.write( "2x - 2y +3(-4) = -4
\n" ); document.write( "2x - 2y - 12 = -4
\n" ); document.write( "2x - 2y = -4 + 12
\n" ); document.write( "2x - 2y = +8
\n" ); document.write( ":
\n" ); document.write( "Using these two equations multiply the 1st, two unknown equation, by -2
\n" ); document.write( "Add to the above equation
\n" ); document.write( "6x + 2y = -32
\n" ); document.write( "2x - 2y = 8
\n" ); document.write( "-----------------addition eliminates y, find x
\n" ); document.write( "8x + 0y = -24
\n" ); document.write( "x = \"%28-24%29%2F8\"
\n" ); document.write( "x = -3
\n" ); document.write( ":
\n" ); document.write( "Using the 1st original equation substitute -3 for x and -4 for z
\n" ); document.write( "-4x + 4y - 2z = -8
\n" ); document.write( "-4(-3) + 4y - 2(-4) = -8
\n" ); document.write( "+12 + 4y + 8 = -8
\n" ); document.write( "4y + 20 = -8
\n" ); document.write( "4y = -8 - 20
\n" ); document.write( "4y = -28
\n" ); document.write( "y = \"%28-28%29%2F4\"
\n" ); document.write( "y = -7
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check solutions of x=-3; y=-7; z=-4 in the 2nd original equation:
\n" ); document.write( "-3x - y + 4z = 0
\n" ); document.write( "-3(-3) - (-7) + 4(-4) = 0
\n" ); document.write( "+9 + 7 - 16 = 0; confirms our solutions \n" ); document.write( "
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