x³ + x²y - xy² - y³
= x²( x + y) - y²( x + y)
= (x + y)(x² - y²)
= (x + y)(x + y)(x - y)
= (x + y)²(x - y)
x² - y² - 4x + 4y
= (x - y)(x + y) - 4(x - y)
= (x - y)(x + y - 4)
x² - 5x + 4
= x² - x - 4x + 4
= x(x - 1) - 4(x - 1)
=(x - 1)(x - 4)
$x^{4}$ - 4x³ - 8x² + 8x
= x(x³ - 4x² - 8x + 8)
= x(x³ + 2³ - 4x² - 8x)
= x[(x + 2)(x² - 2x + 4) - 4x(x + 2)]
= x(x + 2)(x² - 2x + 4 - 4x)
= x(x + 2)(x² - 6x + 4)
Chúc bạn học tốt!!!
*Xin ctlhn ạ!
