Question

Bài 1: Thực hiện phép tính

a, (5x-2y)(x\(^2\)-xy+1)

b, (x-1)(x+1)(x+2)

c, \(\dfrac{1}{2}\)x\(^2\)y\(^2\)(2x+y)(2x-y)

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

e, (x-7)(x+5)-(2x+1)(3-x)

Answer 1

a: =5x^3-5x^2y+5x-2x^2y+2xy^2-2y

=5x^3-7x^2y+2xy^2+5x-2y

b: =(x^2-1)(x+2)

=x^3+2x^2-x-2

c: =1/2x^2y^2(4x^2-y^2)

=2x^4y^2-1/2x^2y^4

d: =(x^2-1/4)(4x-1)

=4x^3-x^2-x+1/4

e: =x^2-2x-35+(2x+1)(x-3)

=x^2-2x-35+2x^2-6x+x-3

=3x^2-7x-38