Question

[Nguyễn Đức Tài]

 a)a² – 4b²                                        b) x² – y² + 6y - 9                                         

c) (2a + b)² – a²                     d) 16(x – 1)² – 25(x + y)²

e)x² + 10x + 25                f) 25x² – 20xy + 4y²

      g)9x⁴ + 24x² + 16             h) x³ – 125

      i)x⁶ – 1                            k) x³ + 15x² + 75x + 125

Answer 1

[Nguyễn Hải Phong]

a) (a - 2b)x(a + 2b)
b) x²-(y-3)²
 => (x-y+3)(x+y-3)
c) (2a + b - a)(2a + b + a)
=> (a+b)(3a+b)
d) (4(x - 1))² - (5(x + y))²
⇔ (4x - 4 - 5x - 5y)(4x - 4 + 5x + 5y)
⇔ -(x + 5y + 4)(9x + 5y + -4)
e) (x + 5)²
f) (5x - 2y)²
h) (x - 5)(x² + 5x + 25)

k) (x + 5)³