Dạng `2` :
Bài `1` :
`\text{a)}`
`-6x^3zy + 2/3yx^3z`
`= (-6+ 2/3)x^3yz`
`= ({-18}/3 + 2/3)x^3yz`
`= {-16}/3x^3yz`
`\text{b)}`
`-x^2y + 2/3yx^2 - 5x^2y`
`= (-1+2/3 - 5) x^2y`
`= -16/3x^2y`
`\text{c)}`
`({-2}/17x^3y^5) . 34/5x^2y`
`= ({-2}/17 . 34/5 )(x^3 . x^2)(y^5 . y )`
`= {-4}/5x^5y^6`
`\text{d)}`
`1/2x^2(-2x^2y^2z) . {-1}/3x^2y^3`
`= (1/2 . (-2) . {-1}/3)( x^2x^2x^2)(y^2y^3) . z`
`= 1/3x^6y^5z`
Bài `3` :
`\text{a)}`
`A = ({-3}/7x^2y^2z)({-42}/9 xy^2z^2)`
`A = ({-3}/7 . {-42}/9)(x^2x)(y^2y^2)(z z^2)`
`A =2 x^3y^4z^3`
`\text{b)}`
`-` Hệ số : `2`
`-` Bậc : `3 +4+3 = 10`
`\text{c)}`
Thay `x = 2 ; y = 1 ; z = -1` vào `A` ta được :
`A = 2 . 2^3 . 1^4 . (-1)^3 = -16`
