a) 14x²y - 21xy² + 28x²y²
= 7xy(2x - 3y + 4xy)
b) x² - 6x + 9 - y²
= (x - 3)² - y²
= (x - 3 - y)(x - 3 + y)
c) x(x + y) - 3x - 3y
= x(x + y) - 3(x + y)
= (x + y)(x - 3)
d) x² + (x - 2)² - 4
= x² + (x - 2 - 2)(x - 2 + 2)
= x² +(x - 4).x
= x.(x + x - 4)
= x(2x - 4)
= 2x(x - 2)
e) 3(x - y) - 5x(x - y)
= (x - y)(3 - 5x)
f) x(y - 1) - y(y - 1)
= (y - 1)(x - y)
f) x(y - 1) - y(y - 1)
= (y - 1)(x - y)
g) 10x(x - y) - 8y(x - y)
= (x - y)(10x - 8y)
= (x - y)(5x - 4y).2
h) 2x² + 5xy - 3x³
= x(2x + 5y - 3x²)
Chúc bạn học tốt
