Question

Phân tích các đa thức sau thành nhân tử:

a,(x+y)^2-9x^2

b,x^2+4-y^2+4x

c,x^2-3x+xy-3y

d,14x^2y-21xy^2+28x^2y^2

e,8x^3-1/8

f,10x(x-y)-8y(y-x)

g,x^2+6x+9

h,3x^2-3xy-5x+5y

i,3x^2+6xy+3y^2-3z^2

^ là mũ nhá mọi người

 

Answer 1

ngất

Answer 2

a)

(x+y)^2-9x^2 = (x+y-9x)(x+y+9x)=(y-8x)(10x+y)

Answer 3

b,x^2+4-y^2+4x=(x²-y²)+(4+4x)=(x-y)(x+y)+4(1+x)

 

Answer 4

c,x^2-3x+xy-3y=(x²+xy)-(3x+3y)=x(x+y)-3(x+y)=(x-3)(x+y)

Answer 5

d,14x^2y-21xy^2+28x^2y^2=7xy[2x(1+2y)+3y]

 

Answer 6

e,8x^3-1/8=(2x)³-(1/2)³=(2x-1/2)[(2x)²+2x1/2+(1/2)²=(2x-1/2)(4x²+x+1/4)

 

Answer 7

f,10x(x-y)-8y(y-x)= 10x(x-y)+8y(x-y)=(10x+8y)(x-y)=2(5x+4y)(x-y)

Answer 8

g,x^2+6x+9=(x+3)²

Answer 9

h,3x^2-3xy-5x+5y=(3x²-3xy)-(5x-5y)=3x(x-y)-5(x-y)=(3x-5)(x-y)

Answer 10

i,3x^2+6xy+3y^2-3z^2=3(x²+2xy+y²-z²)=3[(x+y)²-z^2] =3(x+y+z)(x+y-z)