Answer:
Step-by-step explanation:
6. x² + 8x + 7
= x² + 7x + x + 7
= x (x + 7) + 1 (x + 7)
= (x + 1) (x + 7)
Option D is the answer.
7. x² - x - 72
= x² - 9x + 8x - 72
= x(x - 9) + 8(x - 9)
Option B is the answer.
8. x² - 49
= (x - 7) (x + 7) [formula used a² - b² = (a-b)]
Option D is the answer.
9. 9x² - 54x + 72
= 9(x² - 6x + 8)
= 9(x² - 4x - 2x + 8)
= 9[x(x-4) -2 (x-4)]
= 9[(x - 2) (x - 4)]
= Option A is the answer.
10. x⁴ - 3x³ - 10x²
= x² (x² - 3x - 10)
= x² (x² - 5x + 2x - 10)
= x² [x (x-5) + 2 (x-5)]
= x² (x+2) (x-5)
Option A is the answer.
