Bài 3:

3: \(6x\left(x-y\right)-9y^2+9xy\)

\(=6x\left(x-y\right)+9xy-9y^2\)

\(=6x\left(x-y\right)+9y\left(x-y\right)\)

\(=\left(x-y\right)\left(6x+9y\right)\)

\(=3\left(2x+3y\right)\left(x-y\right)\)

Bài 4:

\(\frac{y}{2x^2-xy}+\frac{4x}{y^2-2xy}=0\)

<=>\(\frac{y}{x\left(2x-y\right)}-\frac{4x}{y\left(2x-y\right)}=0\)

<=>\(\frac{y^2}{xy\left(2x-y\right)}-\frac{4x^2}{xy\left(2x-y\right)}=0\)

 =>y²-(2x)²=0

<=>(y-2x)(y+2x)=0

<=>y-2x=0 hoặc y+2x=0

M chỉ làm đc đến đó thôi!!!!!

a) –4x(5x^2 – 2xy + y^2)

= -20x^3 + 8x^2y - 4xy^2

b) (4x – 1)(2x^2 – x – 1)

= 8x^3 - 4x^2 - 4x - 2x^2 + x + 1

= 8x^3 - 6x^2 - 3x + 1

\(\frac{3x^2y-4x^2y}{2xy+5x}=\frac{-x^2y}{x\left(2y+5\right)}=\frac{-xy}{2y+5}\)

=3x²y-2x+5x

=x(3xy-2+5)

=x(3xy+3)

=3x(xy+1)

mk ko bt cs đúng hơn

3x²y-2x+5x (vì 4x²y rút gọn cho 2xy)
=3x²y+3x

a, \(2x\left(x-2y\right)-2y\left(y-2x\right)=2x^2-4xy-2y^2+4xy=2x^2-2y^2\)

b, \(\left(x-2\right)\left(3x^2+4x-5\right)=3x^3+4x^2-5x-6x^2-8x+10=3x^3-2x^2-13x+10\)

c, \(\left(x+2y\right)\left(x^2-2xy+4y^2\right)=x^3-2x^2y+4xy^2+2x^2y-4xy^2+8y^3=x^3+8y^3\)

a: \(=x-\dfrac{3}{2}+2y\)

b: \(=\dfrac{1}{x\left(y-x\right)}-\dfrac{1}{y\left(y-x\right)}=\dfrac{y-x}{xy\left(y-x\right)}=\dfrac{1}{xy}\)

\(Bài1:\\ a,\left(4x-1\right)\left(2x^2-x-1\right)=4x\left(2x^2-x-1\right)-\left(2x^2-x-1\right)=8x^3-4x^2-4x-2x^2+x+1=8x^3-6x^2-3x+1\\ b,\left(4x^3+8x^2-2x\right):2x\\ =2x\left(2x^2+4x-1\right):2x\\ =2x^2+4x-1\)

\(Bài2:\\ a,2x^3-8x^2+8x=2x\left(x^2-4x+4\right)=2x\left(x-2\right)^2\\ b,2xy+2x+yz+z=2x\left(y+1\right)+z\left(y+1\right)=\left(y+1\right)\left(2x+z\right)\\ c,x^2+2x+1-y^2=\left(x+1\right)^2-y^2=\left(x-y+1\right)\left(x+y+1\right)\)

giúp mk với nhé

sáng mai nộp rồi 

ai nhanh tay mk sẽ k cho