Đáp án:
a) ` 7x^2 + y + 2xy`
b) `4xy + 2x^2 + y^3 + t`
c) `11x - 5x^3 + x^2 + 3/2 y^2 + y^3 + 8xy`
d) `1/6 x^2y + 3/2 xy^2 - 6xy`
e) `1`
f) ` 3x^2yz + 9xyz^2 - xyz`
Giải thích các bước giải:
a) (Có dấu ngoặc tròn ở đây lm j thế bn ==")
`3x^2 + y + xy + 3/2 . 3 . x^2 + y.x+ x^2`
`= 3x^2 + y + xy + 3x^2 + xy + x^2`
`= (3x^2 + 3x^2 + x^2) + y + (xy + xy)`
`= 7x^2 + y + 2xy`
b) `xy + 3xy + x^2 + y^3 + x^2 + t`
`= 4xy + (x^2 + x^2) + y^3 + t`
`= 4xy + 2x^2 + y^3 + t`
c) `8x - x^3 + x^2 + y^2 + 1/2 y^2 + 3x - 4x^3 + y^3 + 8xy`
`= (8x + 3x) + (-x^3 - 4x^3) + x^2 + (y^2 + 1/2 y^2) + y^3 + 8xy`
`= 11x - 5x^3 + x^2 + 3/2 y^2 + y^3 + 8xy`
d) `1/2 x^2y + xy^2 - xy + 1/2 xy^2 - 5xy -1/3 x^2y`
`= (1/2 x^2y - 1/3x^2y) + (xy^2 + 1/2 xy^2) + (-xy - 5xy)`
`= 1/6 x^2y + 3/2 xy^2 - 6xy`
e) `3x^2y - 1/4 xy + 1 -3x^2y + 1/2 xy - 1/4 xy`
`= (3x^2y - 3x^2y) + (-1/4 xy + 1/2 xy - 1/4 xy) + 1`
`= 0 + 0 + 1 =1`
f) `5x^2yz + 8xyz^2 - 3x^2yz - xyz + x^2yz + xyz^2`
`= (5x^2yz - 3x^2yz + x^2yz) + (8xyz^2 + xyz^2) - xyz`
`= 3x^2yz + 9xyz^2 - xyz`
