Đáp án:`+`Giải thích các bước giải:

 ` M=  3x^2yz + 4xy^2z -xyz^2 +x^2y^2z^2 +3`

` N = x^2y^2z^2 +2xyz^2 - 2xy^2z +x^2yz`

`a) M + P = N`

`=>` `P = N - M`

`=>` `P = x^2y^2z^2 +2xyz^2 -2xy^2z +x^2yz - ( 3x^2yz + 4xy^2z -xyz^2 +x^2y^2z^2 +3)`

`=>` `P = x^2y^2z^2 +2xyz^2 -2xy^2z +x^2yz - 3x^2yz - 4xy^2z +xyz^2 -x^2y^2z^2 -3`

`=>` `P = x^2y^2 z^2 - x^2y^2z^2 + 2xyz^2 +xyz^2 - 2xy^2z -4xy^2z - 3x^2yz +x^2yz -3`

`=>` ` P= 3xyz^2 - 6xy^2z -2x^2yz -3`

`b) M -Q =N`

`=>` `Q = M+N`

`=>` `Q= 3x^2yz +4xy^2z -xyz^2 +x^2y^2z^2 +3 +  x^2y^2z^2 +2xyz^2 -2xy^2z +x^2yz `

`=>` `Q =  2x^2y^2z^2 +4x^2yz + 2xy^2z +xyz^2+3`

`c) R - M= N`

`=>` `R = N + M =  x^2y^2z^2 +2xyz^2 -2xy^2z +x^2yz +  3x^2yz + 4xy^2z -xyz^2 +x^2y^2z^2 +3`

`=>` `R = 2x^2y^2z^2 +xyz^2 +2xy^2z +4x^2yz+3`