Question

Bài 1: Thực hiện các phép tính sau:

a)-2xy^2(x^3y-2x^2y^2+5xy^3)

b)(-2x)(x^3-3x^2-x+1)

c)(-10x^3+2/5y-1/3z)(-1/2zy)

d)3x^2(2x^3-x+5)

e)(4xy+3y-5x)x^2y

f)(3x^2y-6xy+9x)(-4/3xy)

Answer 1

\(a,-2xy^2\left(x^3y-2x^2y^2+5xy^3\right)\\ =-2x^4y^3+4x^3y^4-10x^2y^5\\ b,\left(-2x\right)\left(x^3-3x^2-x+1\right)\\ =-2x^4+6x^3+2x^2-2x\\ c,\left(-10x^3+\dfrac{2}{5}y-\dfrac{1}{3}z\right)\left(-\dfrac{1}{2}zy\right)\\ =5x^3yz-\dfrac{1}{5}y^2z+\dfrac{1}{6}yz^2\\ d,3x^2\left(2x^3-x+5\right)=6x^5-3x^3+15x^2\\ e,\left(4xy+3y-5x\right)x^2y=4x^3y^2+3x^2y^2-5x^3y\\ f,\left(3x^2y-6xy+9x\right)\left(-\dfrac{4}{3}xy\right)\\ =-4x^3y^2+8x^2y^2-12x^2y\)