Question

Answer 1

e.

$x^2+2xy+y^2-16=(x^2+2xy+y^2)-4^2=(x+y)^2-4^2$

$=(x+y-4)(x+y+4)$

f.

$x^3+y^3+x+y=(x^3+y^3)+(x+y)$

$=(x+y)(x^2-xy+y^2)+(x+y)=(x+y)(x^2-xy+y^2+1)$

g.

$xy+y^2+2x+2y=(xy+y^2)+(2x+2y)=y(x+y)+2(x+y)$

$=(x+y)(y+2)$

h.

\(x^2+2xy+y^2+x+y=(x^2+2xy+y^2)+(x+y)=(x+y)^2+(x+y)=(x+y)(x+y+1)\)i.

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

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

Answer 2

Lời giải:

a. 

$x-y-x^2+xy=(x-y)-(x^2-xy)=(x-y)-x(x-y)=(1-x)(x-y)$

b. 

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

c.

$xy+y^2+2x+2y=y(x+y)+2(x+y)$

$=(x+y)(y+2)$

d.

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

$=(x-y)(x+y-3)$