Question

Answer 1

Bài 2:

a. 

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

$=8x^3-4x^2y+4x^2y-2xy^2+6xy^2-3y^3$
$=8x^3+4xy^2-3y^3$
b.

$=\frac{9x^5y^8}{2x^3}-\frac{4x^4y^2}{2x^3}+\frac{7x^3}{2x^3}$

$=\frac{9}{2}x^2y^8-2xy^2+\frac{7}{2}$

Answer 2

Bài 3:

a.

$(2x+4)(3x-5x^2y+2)=3x(2x+4)-5x^2y(2x+4)+2(2x+4)$
$=6x^2+12x-10x^3y-20x^2y+4x+8$

$=-10x^3y-20x^2y+6x^2+16x+8$

b.

$=\frac{15x^4}{-5x^2}-\frac{20x^3}{-5x^2}+\frac{10x^2}{-5x^2}$

$=-3x^2+4x-2$

Answer 3

Bài 1:

a.

$(2x+3)(x^2+5x-4)=x^2(2x+3)+5x(2x+3)-4(2x+3)$
$=2x^3+3x^2+10x^2+15x-8x-12$

$=2x^3+13x^2+7x-12$
b.

$(6x^5y^8-4x^4y^2+7x^3):(2x^3)=\frac{6x^5y^8}{2x^3}-\frac{4x^4y^2}{2x^3}+\frac{7x^3}{2x^3}$

$=3x^2y^8-2xy^2+\frac{7}{2}$

 

Answer 4

Bài 4:
a.

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

$=8x^3+4x^2y+6xy^2-4x^2y-2xy^2-3y^3$
$=8x^3+4xy^2-3y^3$
b.

$=\frac{9x^2y^2}{3xy}-\frac{6x^2y^3}{3xy}+\frac{2xy}{3xy}$

$=3xy-2xy^2+\frac{2}{3}$

 

Answer 5

Bài 5:

a.

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

$=6x^2-9x-10x^3y+15x^2y+4x-6$

$=-10x^3y+15x^2y+6x^2-5x-6$

b.

$=\frac{14x^3y^2}{7xy}+\frac{28x^2y}{7xy}-\frac{7xy}{7xy}$

$=2x^2y+4x-1$

Answer 6

Bài 6:

a.

$(3x-2y)(9x^2+6xy+4y^2)=(3x-2y)[(3x)^2+3x.2y+(2y)^2]$

$=(3x)^3-(2y)^3=27x^3-8y^3$
b.

$=\frac{9x^3y^5}{3x^2y^3}-\frac{15x^2y^4}{3x^2y^3}+\frac{6x^4y^3}{3x^2y^3}$

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