Đáp án:
`a)2x^3y^2-2/3x^4y+2/3x^2y^2`
`b)-2x^4y+5/2x^2y^2-x^2y`
`c)=2x^4+6x^3+x^2`
`d)=-9x^6y^2+(5x^6y^5)/3+(3y^6x^4)/2`
Giải thích các bước giải:
`a)(3xy-x^2+y)*2/3x^2y`
`=3xy(2/3x^2y)+(-x^2)(2/3x^2y)+y(2/3x^2y)`
`=2x^3y^2-2/3x^4y+2/3x^2y^2`
`b)(4x^3-5xy+2x)(-1/2xy)`
`=4x^3(-1/2xy)+(-5xy)(-1/2xy)+2x(-1/2xy)`
`=-2x^4y+5/2x^2y^2-x^2y`
`c)2x^2(x^2+3x+1/2)`
`=2x^2*x^2+2x^2*3x+2x^2*1/2`
`=2x^4+6x^3+x^2`
`d)-3/2x^4y^2(6x^2-10/9x^2y^3-y^4)`
`=(-3/2x^4y^2)6x^2-(-3/2x^4y^2)10/9x^2y^3-(-3/2x^4y^2)y^4`
`=-9x^6y^2+(5x^6y^5)/3+(3y^6x^4)/2`