A = 8x - 12
A = 4×2x - 4×3
A = 4 ×(2x - 3)
A = 4 (2x - 3)
B = 7x² - 21x
B = 7x × x - 7x × 3
B = 7x × (x - 3)
B = 7x(x - 3)
C = (x - 5) (x + 2) - (x - 5)(5x + 1)
C = (x - 5) × [ (x + 2) - (5x + 1)]
C = (x - 5) × [x + 2 - 5x - 1 ]
C = (x - 5) (- 4x + 1)
D = 2x + 3 + 5x(2x + 3)
D = (2x + 3) × 1 + (2x + 3) × 5x
D = (2x + 3) × (1 + 5x)
D = (2x + 3)(1 + 5x)
