Question

Giải giúp em vs ạ :(((. Làm đến câu 13 ạ.

Answer 1

`1. 2x^2y^5 - 5x^3y - 7x^2y^5 + 4x^3y - 8x^2y^5 + 6x^3y `

`= (2x^2y^5 - 7x^2y^5 - 8x^2y^5) + (-5x^3y + 4x^3y + 6x^3y)`

`= -13x^2y^5 + 5x^3y`

 

`2. -5x^2y + 12xy^2 + 7xy -10xy +3x^2y - 4xy^2`

`= (-5x^2y + 3x^2y) + (12xy^2-4xy^2) + (7xy-10xy)`

`= -2x^2y + 8xy^2 - 3xy`

 

`3. 15x^2y^3 + 7x^2 - 8x^3y^2 - 12x^2 + 11x^3y^2 -12x^2y^3`

`= (15x^2y^3 -12x^2y^3) + ( 7x^2 -12x^2) + ( 8x^3y^2 - 11x^3y^2)`

`= 3x^2y^3 -5 x^2-3x^3y^2`

 

`4. 7/2 x^4y^3 - 5x^2y^5 -6y + 8x^2y^5 - 1/3 x^4y^3 -1/2 y`

`= (7/2 x^4y^3 -1/3x^4y^3) + ( 5x^2y^5 + 8x^2y^5) + (-6y-1/2y)`

`= 19/6 x^4y^3 + 13x^2y^5 - 13/2y`

 

`5. 4/3xy^2 - 2x^3y^5 + 1/4 xy^2 + 7xy -1/5x^3y^5 -5/4xy`

`= (4/3xy^2 + 1/4xy^2) + (2x^3y^5 -1/5x^3y^5) + ( 7xy-5/4xy)`

`= 19/12xy^2 + 9/5x^3y^5 + 23/4xy`

 

`6. 1/4x^4y^5 - 2x^3y^2 + 1/2x^2y^4 -1/3x^3y^2 + 1/3x^2y^4 -x^4y^5`

`=(1/4x^4y^5 - x^4y^5)+ (2x^3y^2 -1/3x^3y^2) + ( 1/2x^2y^4 + 1/3x^2y^4)`

`= -3/4x^4y^5 + 5/3x^3y^2 + 5/6x^2y^4`

Answer 2

`7. 5x^2y^3 -1/2xy^2 - 11/2x^2y^3 + xy^2 - 3x^3y^4 + 1/5x^3y^4`

`=(5x^2y^3 - 11/2 x^2y^3) + (-1/2xy^2 + xy^2) + (-3x^3y^4 + 1/5x^3y^4)`

`=-1/2x^2y^3 + 1/2xy62 -14/5x^3y^4`

 

`8. 4x^5y^7 - 1/3x^2y^6 + 1/2x^4y - 3/4x^5y^7 + x^2y^6 - 1/6x^4y`

`= (4x^5y^7 - 3/4x^5y^7) + ( 1/3x^2y^6 + x^2y^6) + ( 1/2x^4 - 1/6x^4y)`

`= 13/4x^5y^7 + 4/3x^2y^6 + 1/3x^4y`

 

`9. 2/5xy^2 - 3x^3y + 1/3x^4y^3 - 1/2x^3y -1/4x^4y^3 + xy^2`

`= (2/5 xy^2 + xy^2) + ( -3x^3y - 1/2x^3y) + (1/3x^4y^3 - 1/4x^4y^3)`

`= 7/5xy^2 -7/2x^3y + 1/12x^4y^3`

 

`10. 3x^5y - 1/3xy^4 + 3/4x^2y^3 - 1/2x^5y + 2xy^4 - x^2y^3`

`= (3x^5y - 1/2 x^5y) + (-1/3xy^4 +2xy^4) + ( 3/4x^2y^3 -x^2y^3)`

`= 5/2x^5y + 5/3xy^4 -1/4x^2y^3`

 

`11. 5/4xy - 3x^2y^7 + 1/2 xy^3 + 1/2 xy + 1/4x^2y^7 + xy^3`

`= (5/4xy -1/2xy) + ( -3x^2y^7 + 1/4x^2y^7) + (1/2xy^3 + xy^3)`

`= 3/4xy -11/4x^2y^7 + 3/2xy^3`

 

`12. 1/4x^2 - (5/2x - 7/5x^2 -1) + (5/2x - 1 + 1/2x)`

`= 1/4x^2 - 5/2x + 7/5x^2 + 1 + 5/2x -1 + 1/2x`

`= ( 1/4x^2 + 7/5x^2) + ( -5/2x + 5/2x + 1/2x ) + (1-1)`

`= 33/20x^2 + 1/2x `

 

`13. 5/2x^2y^5 - (1/2x^3y^4 -3/2xy+5/2x^2y^5) + (1/2x^3y^4 -1/2xy)`

`= 5/2x^2y^5 - 1/2 x^3y^4 + 3/2 xy - 5/2x^2y^5 + 1/2x^3y^4 - 1/2xy`

`= ( 5/2x^2y^5 - 5/2x^2y^5) + ( -1/2x^3y^4 + 1/2x^3y^4) + ( 3/2xy - 1/2xy)`

`= xy`