Bài 1

• a) 4x² +28x +49

(2x + 7)² = (2x + 7)(2x + 7)

• b) 16y² - 8y | 1

(4y - 1)² = (4y - 1)(4y - 1)

• c) 4a +20ab +256²

(4a + 16b)² = (4a + 16b)(4a + 16b)

• d) 9x² - 6xy | y

(3x - 2y)² = (3x - 2y)(3x - 2y)

Bài 2

• a) a 12a 48a | 64

(a + 8)³ = (a + 8)(a + 8)(a + 8)

• b) 27r -54x³y +36xy² + 8y³

(3r - 2xy)³ = (3r - 2xy)(3r - 2xy)(3r - 2xy)

• c) x²9x² | 27x-27

(3x)³ = (3x)(3x)(3x)

• d) 8a-12a²b | 6ab²-6³

(4a - 3b)³ = (4a - 3b)(4a - 3b)(4a - 3b)

Bài 3

• a) 25²-16

(5²)² - 4² = 5²(5² - 4) = 25(21) = 525

• c) 8x² +1

(2x)² + 1² = 2x² + 2x + 1 - 2x = (2x + 1)² - 1

• d) 8x² - 125

(2x)² - 5² = (2x + 5)(2x - 5)

• b) 16a²9b²

16a² * 9b² = (4a * 3b)²

• d) 125x² +27y³

125x² + 27y³ = 5²x² + 3³y³ = (5x * 3y)²

• e) 27x² - y²

27x² - y² = 3²x² - y² = (3x)² - y² = (3x + y)(3x - y)