Question

Phân tích các đa thức sau thành nhân tử

a, x² -5x + xy - 5y

b, 4x² - (x - 2)²

c, 48x²y² - 3y² + 6xy - 3x²

d, 2x² - 5x - 7

Answer 1

a) (x² + xy) - (5x + 5y) = x(x + y) - 5(x + y)

= (x + y)(x - 5)

b) (2x - x +2 )(2x + x - 2) = (x + 2)(x - 2)

d) 2x² + 2x - 7x - 7 = (2x² + 2x) - (7x + 7)

= 2x(x + 1) - 7(x + 1) = (x + 1)(2x - 7)

Answer 2

c) 3(16x²y² - y² + 2xy - x²)

= 3\(\left[16x^2y^2-\left(y^2-2xy+x^2\right)\right]\)

= 3\(\left[16x^2y^2-\left(y-x\right)^2\right]\)

= 3(4xy - y + x)(4xy + y - x)