Question

[Nguyễn Khoa Nguyên]

BT: Rút gọn

a) x³ ( x² - 2x - 1) - x² (x+1)

b) (2x² + x + 1) (x-3)

c) (3x² - xy) ( 2xy² - x + 1)

d) (x³ + x²y + y³) (x-y)

e) ( x+\(\dfrac{1}{2}\) ) (x-\(\dfrac{1}{2}\) ) (4x-1)

Answer 1

[Nguyễn Lê Phước Thịnh]

a; \(=x^5-2x^4-x^3-x^3-x^2=x^5-2x^4-2x^3-x^2\)

b: \(=2x^3-6x^2+x^2-3x+x-3\)

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

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

d: \(=x^3-x^3y+x^3y-x^2y^2+xy^3-y^4\)

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