a) \(9\left(x+y-1\right)^2-4\left(2x+3y+1\right)^2\)

\(=\left(3x+3y-3\right)^2-\left(4x+6y+2\right)^2\)

\(=\left(3x+3y-3-4x-6y-2\right)\left(3x+3y-3+4x+6y+2\right)\)

\(=\left(-x-3y-5\right)\left(7x+9y-1\right)\)

b) \(3x^4y^2+3x^3y^2+3xy^2+3y^2\)

\(=\left(3x^4y^2+3xy^2\right)+\left(3x^3y^2+3y^2\right)\)

\(=3xy^2\left(x^3+1\right)+3y^2\left(x^3+1\right)\)

\(=\left(3xy^2+3y^2\right)\left(x^3+1\right)\)

\(=3y^2\left(x+1\right)\left(x+1\right)\left(x^2-x+1\right)\)

\(=3y^2\left(x+1\right)^2\left(x^2-x+1\right)\)

c) \(\left(x+y\right)^3-1-3xy\left(x+y-1\right)\)

\(=\left(x+y-1\right)\left[\left(x+y\right)^2+x+y+1\right]-3xy\left(x+y-1\right)\)

\(=\left(x+y-1\right)\left(x^2+2xy+y^2+x+y+1-3xy\right)\)

\(=\left(x+y-1\right)\left(x^2+x+y^2+y+1-xy\right)\)

a,(2x-y)²+(2x+y)²=(2x²-2*2xy+y²)+(2x²+2*2xy+y²)

                            =2x²-4xy+y²+2x²+4xy+y²

                            =4x²+2y²

Đề bài là gì sao không ghi rõ?? 

A = 2x² - 6xy - 3xy - 6y - 2x² + 8xy + 6y

   = - xy

  = \(\frac{2}{3}\)\(x\)\(\frac{3}{4}\)

  = \(\frac{1}{2}\)

mk đang bận mấy câu kia tương tự nha

a)\(\left(x+y\right)^2:\left(x+y\right)=x+y\)

b)\(\left(x-y\right)^5:\left(y-x\right)^4=\left(x-y\right)^5:\left(x-y\right)^4=x-y\)

c)\(\left(5x^4-3x^3+x^2\right):3x^2=\frac{5}{3}x^2-x+\frac{1}{3}^{ }\)

d)\(\left(x^3y^3-\frac{1}{2}x^2y^3+x^3y^2\right):\frac{1}{2}x^2y^2=2xy-y+x\)

a, \(x^2\) + 6x + 5 = 0
=>\(x^2\) + x + 5x +5 = 0
=>x(x + 1) + 5(x + 1) = 0
=>(x + 1)(x + 5) = 0
=> x + 1 =0 hoặc x + 5 =0
=> x = -1 hoặc x = -5

c) \(\dfrac{x+3}{x-1}+\dfrac{2x+5}{x-1}+\dfrac{14-3x}{1-x}\)

\(=\dfrac{x+3}{x-1}+\dfrac{2x+5}{x-1}-\dfrac{14-3x}{x-1}\)

\(=\dfrac{x+3+2x+5-14+3x}{x-1}\)

\(=\dfrac{6x-6}{x-1}\)

\(=\dfrac{6\left(x-1\right)}{x-1}\)

\(=6.\)

\(2x\left(x^2-7x-3\right)=2x^3-14x-6x\)

\(4xy^2\left(-2x^3+y^2-7xy\right)=-8x^4y^2+4xy^5-28x^2y^3\)

all ạ

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

b. \(\left(5-x^2\right)\left(5+x^2\right)=25+5x^2-5x^2-x^4=-x^4+25\)

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

\(=8x^3-y^3\)

d. \(\left(5-3x\right)^2=25-30x+9x^2\)

e. \(\left(5x-1\right)^3=125x^3-75x^3+15x-1\)

f. \(\left(x+3\right)\left(x^2-3x+9\right)=x^3-3x^2+9x+3x^2-9x+27=x^3+27\)

h. \(\left(2x^2+3y\right)^2=4x^4+12x^2y+9y^2\)

a) (2+xy)² = 2²+4xy+(xy)² = 4 + 4xy +x²y²

b)  ( 5 - x^2 ) . ( 5 + x^2 ) = 5²-x⁴=25-x⁴

c) ( 2x - y ) . ( 4x^2 + 2xy + y^2 )  = 8x³-y³

d)(5-3x)²=5²-2.5.3x+9x²=25-30x+9x²

e) (5x-1)³=(5x)³-3.(5x)².1+3.5x.1-1 =125x³-75x²+15x-1

f) (x+3)(x²-3x+9)=(x+3)(x²-3x+3²)=x³+27

g) -x³+3x²-3x+1 =(−x+1)(x−1)(x−1)= -(x-1)³

h) (2x²+3y)²=4x⁴+2.2x².3y+9y²=4x⁴+12x²y+9y²