help me plss

Bài 2: 

\(\dfrac{x^4-x^3+3x^2-x+a}{x^2-x+2}\)

\(=\dfrac{x^4-x^3+2x^2+x^2-x+2+a-2}{x^2-x+2}\)

\(=x^2+1+\dfrac{a-2}{x^2-x+2}\)

Để A chia hết cho B thì a-2=0

hay a=2

:/

a) \(x\left(xy+1\right)+y\left(xy-1\right)-xy\left(x+y\right)\)

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

\(=x-y\)

a, \(x\left(xy+1\right)+y\left(xy-1\right)-xy\left(x+y\right)\)

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

\(=x-y\)

b, \(-x\left(x^2+x+1\right)+\frac{1}{2}x^2\left(2x-4\right)+x\left(x+1\right)-2\)

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

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

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

bậc 5, hệ số 3 

bạn xem lại đề B nhé 

A=15x²y²+7x²-8x³y²-12x²+11x³y²-12x²y²

A= (15x²y²-12x²y²)+(7x²-12x²)+(-8x³y²+11x³y²)

A= 3x²y²-5x²+3x³y²

Bậc là: 5

Hệ số cao nhất: 3

\(B=3x^5y+\left(\dfrac{-1}{3}\right)xy^4+34x^2y^3-\dfrac{1}{2}x^5y+2xy^4-x^2y^3\\ B=\dfrac{5}{2}x^5y+\dfrac{7}{3}xy^4-\dfrac{1}{4}x^2y^3\)

bậc là:6

hệ số cao nhất là:\(\dfrac{7}{3}\)

a) x² + xy + y - 1 = (x² - 1) + (xy + y) = (x - 1)(x + 1) + y(x + 1) = (x + 1)(x + y - 1)

b) 4 - x² + 2xy - y² = 4 - (x² - 2xy + y²) = 4 - (x - y)² = (x - y + 2)(4 - x + y) 

c) 8x² - 18y² = 2(4x² - 9y²) = 2[(2x)² - (3y)²] = 2(2x - 3y)(2x + 3y)

d) 8x³ - 4x² - 6xy - 9y² - 27y³

= (8x³ - 27y³) - (4x² + 6xy + 9y²)

= (2x - 3y)(4x² + 6xy + 9y²) - (4x² + 6xy + 9y²)

= (2x - 3y - 1)(4x² + 6xy + 9y²)

e) 4x² - x - 3 = 4x² - 4x + 3x - 3 = 4x(x - 1) + 3(x - 1) = (x - 1)(4x + 3)

f) 4x² - 8x + 3 = 4x² - 2x - 6x + 3 = 2x(2x - 1) - 3(2x - 1) = (2x - 3)(2x - 1)

cảm ơn bạn

mấy bn ơi, giúp mk nhanh vs nha!!!!!!!!!!!

a/ A = 2x² + y² - 2xy - 2x + 3

= (x² - 2xy + y²) + (x² - 2x + 1) + 2

= (x - y)² + (x - 1)² + 2\(\ge2\)