Question

PTĐTTNT

a/ 5a^2 - 5

b/ ( a^2 + 9 )^2 - 36a^2

c/ m^2 + 9 - 6m - x^2 - 4y^2 + 4xy

d/ -12x^2y + 75xy^2

e/ 8xy^3 + x . ( x - y )

f/ 12x^2 + 1 - 8x

Answer 1

a) 5a² - 5

= 5(a² - 1)

= 5(a - 1)(a + 1)

b) (a² + 9)² - 36a²

= (a² + 9)² - (6a)²

= (a² + 9 - 6a)(a² + 9 + 6a)

= (a - 3)²(a + 3)²

c) m² + 9 - 6m - x² - 4y² + 4xy

= (m² - 6m + 9) - (x² - 4xy + 4y²)

= (m - 3)² - (x - 2y)²

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

Answer 2

d) -12x²y + 75xy²

= -3xy(4x - 15y)
e) 8xy³ + x(x - y)

= x(8y³ + x - y)

f) 12x² + 1 - 8x

= 12x² - 2x - 6x + 1

= (12x² - 2x) - (6x - 1)

= 2x(6x - 1) - (6x- 1)
= (6x - 1)(2x - 1)