Question

bài 11; thực hiện phép tính 

1) (3x³ - xy² + 4x) + (- 2x³ + xy² + 3x)

2) (x² + y - x²y² -1) + (x² - 2y + xy + 1)

3) ( 5x²y + 5x + 3 ) + (xyz - 4x²y + 5x - 2)

4) (xyz - 4x²y + 5x - 2) - ( 5x²y + 5x + 3 )

Answer 1

1: \(\left(3x^3-xy^2+4x\right)+\left(-2x^3+xy^2+3x\right)\)

\(=\left(3x^3-2x^3\right)+\left(-xy^2+xy^2\right)+\left(4x+3x\right)\)

\(=x^3+7x\)

2: \(\left(x^2+y-x^2y^2-1\right)+\left(x^2-2y+xy+1\right)\)

\(=\left(x^2+x^2\right)+\left(y-2y\right)+\left(-x^2y^2+xy\right)+\left(-1+1\right)\)

\(=2x^2-y-x^2y^2+xy\)

Answer 2

`3) (5x^2y + 5x + 3) + (xyz - 4x^2y + 5x - 2)`

`= 5x^2y + 5x + 3 + xyz - 4x^2y + 5x - 2`

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

`= x^2y + 10x + xyz + 1`

`4)(xyz - 4x^2y + 5x - 2) - (5x^2y + 5x + 3)`

`=xyz - 4x^2y + 5x - 2 - 5x^2y - 5x - 3`

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

`= -9x^2y + xyz - 5`