Bài 3: 

a: Ta có: C=A+B

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

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

b: Ta có: C+A=B

\(\Leftrightarrow C=B-A\)

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

\(=-x^2y^2+3y-xy-2\)

a. = 2xy + 2x² - 4xy² - 2

a,  2xy +2x² - 4xy² - 2     ;    b, -3x²y²  -2x²y + y       ;          c, 3x³ - 2y - 3

Chọn C

Đề yêu cầu gì thế em?

giải bài thoi ạ

a: A=x^2y(2/3+3+1)=14/3*x^2y

=14/3*3^2*(-1/7)

=-2*3=-6

\(a,15x^3y^2-9x^3y^3+6x^3y^3\\ b,12x^3+6x^2y-2x-6x^2y-3xy^2-y\\ =12x^3-2x-3xy^2-y\\ c,4x^2y^3-1\)

\(a,=3x^3y^3-3x^2y^3+3x^2y^4+3xy^5\\ b,=\left(2x^3-6x^2+10x-3x^2+9x-15\right):\left(x^2-3x+5\right)\\ =\left[2x\left(x^2-3x+5\right)-3\left(x^2-3x+5\right)\right]:\left(x^2-3x+5\right)\\ =2x-3\\ c,=\left[x^2\left(x-3\right)+\left(x-3\right)\right]:\left(x-3\right)=x^2+1\)

a) \(\left(\dfrac{3}{5}a^6x^3+\dfrac{3}{7}a^3x^4-\dfrac{9}{10}ax^5\right):\dfrac{3}{5}ax^3\)

\(=\dfrac{\dfrac{3}{5}a^6x^3+\dfrac{3}{7}a^3x^4-\dfrac{9}{10}ax^5}{\dfrac{3}{5}ax^3}\)

\(=\dfrac{\dfrac{3}{5}ax^3\left(a^5+\dfrac{5}{7}a^2x-\dfrac{3}{2}x^2\right)}{\dfrac{3}{5}ax^3}\)

\(=a^5+\dfrac{5}{7}a^2x-\dfrac{3}{2}x^2\)

b) \(\left(9x^2y^3-15x^4y^4\right):3x^2y-\left(2-3x^2y\right)\cdot y^2\)

\(=\dfrac{3x^2y\left(3y^2-5x^2y^3\right)}{3x^2y}-2y^2+3x^2y^3\)

\(=3y^2-5x^2y^3-2y^2+3x^2y^3\)

\(=y^2-2x^2y^3\)

c) \(\left(6x^2-xy\right):x+\left(2x^3y+3xy^2\right):xy-\left(2x-1\right)x\)

\(=\dfrac{6x^2-xy}{x}+\dfrac{2x^3y+3xy^2}{xy}-x\left(2x-1\right)\)

\(=\dfrac{x\left(6x-y\right)}{x}+\dfrac{xy\left(2x^2+3y\right)}{xy}-2x^2+x\)

\(=6x-y+2x^2+3y-2x^2+x\)

\(=7x+2y\)

d) \(\left(x^2-xy\right):x+\left(6x^2y^5-9x^3y^4+15x^4y^2\right):\dfrac{3}{2}x^2y^3\)

\(=\dfrac{x^2-xy}{x}+\dfrac{6x^2y^5-9x^3y^4+15x^4y^2}{\dfrac{3}{2}x^2y^3}\)

\(=\dfrac{x\left(x-y\right)}{x}+\dfrac{\dfrac{3}{2}x^2y^2\left(4y^3-6xy^2+10x^2\right)}{\dfrac{3}{2}x^2y^3}\)

\(=x-y+\dfrac{4y^3-6xy^2+10x^2}{y}\)