Đáp án:
↓↓
Giải thích các bước giải:
`a)`
`x^3y + 5x^3y + (–3x^3y)`
`=x^3y+5x^3y-3x^3y`
`=3x^3y`
`b)`
`–3x^5y^4 + 3x^5y^4 –7x^5y^4 + 5x^5y^4`
`=-2x^5y^4`
`c)`
`-2/3xy.(–3yz) + xy^2z – xy^2z`
`=2/xz`
`d)`
`1/2x^4y-3/2x^4y+5/3x^4y-x^4y`
`=1/4x^4y`
`e)`
`–x^5yz + 6x^5yz – 5x^5yz`
`=x^5yz.`