M+N=(5xyz-5x\(^2\)+8xy+5) + (3x\(^2\)+2xyz-8xy-7+y\(^2\))
=(5xyz+2xyz)-(5x\(^2\)+3x\(^2\))+(8xy-8xy)+(5-7)
=7xyz-2x\(^2\)-2
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M+N=(5xyz -5x2 +8xy+5)+(3x2 +2xyz -8xy-7+y2)
=5xyz -5x2 +8xy+5+3x2 +2xyz -8xy-7+y2
=(5xyz-2xyz)+(5x2+3x2)+(8xy-8xy)+(5-7)+y2
=3xyz+8x2+0+(-2)+y2
=3xyz+8x2+(-2)
M-N=(5xyz -5x2 +8xy+5)-(3x2 +2xyz -8xy-7+y2)
=5xyz -5x2 +8xy+5-3x2 +2xyz -8xy-7+y2
=(5xyz-2xyz)-(5x2+3x2)+(8xy-8xy)+(5-7)+y2
=3xyz-8x2+0+(-2)+y2
N-M=(3x2 +2xyz -8xy-7+y2)-(5xyz -5x2 +8xy+5)
=3x2 +2xyz -8xy-7+y2-5xyz -5x2 +8xy+5
=(3x2-5x2)+(2xyz-5xyz)-(8xy-8xy)-(7+5)+y2
=-2x2+(-3xyz)-0-12+y2
M+N = (5xyz-5x2 +8xy+5) +(3x2 +2xyz-8xy-7+y2)
= 5xyz - 5x2 +8xy +5 +3x2 + 2xyz - 8xy -7 +y2
= ( 5xyz + 2xyz ) + (-5x2 +3x2) + ( 8xy - 8xy ) + ( 5-7) + y2
= 7xyz + (-2x2) + (-2) + y2
M-N = ( 5xyz - 5x2 +8xy +5) - ( 3x2 +2xyz - 8xy - 7 +y2 )
= 5xyz - 5x2 + 8xy + 5 -3x2 - 2xyz + 8xy + 7 -y2
= ( 5xyz - 2xyz ) + ( -5x2 - 3x2 ) + ( 8xy+8xy) + ( 5+7) -y2
= 3xyz -(-8x2) + 16xy + 12-y2
N-M = ( 3x2 + 2xyz - 8xy -7+y2 ) - ( 5xyz - 5x2 + 8xy +5)
= 3x2 + 2xyz - 8xy - 7+y2 - 5xyz+ 5x2 - 8xy - 5
=( 3x2 + 5x2) + ( 2xyz - 5xyz) + (-8xy - 8xy ) + ( -7-5) + y2
= 8x3 - 3xyz - 16xy - 12+y2
