2x^2-5xy-3y^2

 = 2^x + xy - 6xy - 3y^2  

= x(2x + y) - 3y(2x + y)  

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

Lời giải:

$A=x^2-8xy+15y^2=x^2-3xy-(5xy-15y^2)$

$=x(x-3y)-5y(x-3y)=(x-3y)(x-5y)$

$B=2x^2-5xy+2y^2=(2x^2-4xy)-(xy-2y^2)$

$=2x(x-2y)-y(x-2y)=(2x-y)(x-2y)$

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

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

a/ \(\left(x+3y\right)\left(2x-y\right)\)

b/ \(\left(x^2+2\right)\left(x^2-2\right)\left(x^2-2x+2\right)\left(x^2+2x+2\right)\)

b/ \(x^8-16=\left(x^4+4\right)\left(x^4-4\right)\)

\(=\left[\left(x^4+4x^2+4\right)-4x^2\right]\left(x^2-2\right)\left(x^2+2\right)\)

\(=\left[\left(x^2+2\right)^2-4x^2\right]\left(x^2-2\right)\left(x^2+2\right)\)

\(=\left(x^2+2+2x\right)\left(x^2+2-2x\right)\left(x^2-2\right)\left(x^2+2\right)\)

\(A=2x^2-5xy-3y^2\)

\(A=2x^2-6xy+xy-3y^2\)

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

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

d)  \(2x^2-3x-27\)

\(=\left(2x^2+6x\right)-\left(9x+27\right)\)

\(=2x\left(x+3\right)-9\left(x+3\right)\)

\(=\left(2x-9\right)\left(x+3\right)\)

e)  \(2x^2-5xy-3y^2\)

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

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

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

5 x² - 5xy+2x−2y = 2x ( x - y) + 2( x - y) = 2( x + 1)( x - y)

a) \(=x^2+4xy+4y^2-y^2\)

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

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

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

b) \(=2x^2-4xy-xy+2y^2\)

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

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