A = 9a ( 8a - 7) - (8a - 7)  B= ( 6x + 1) (2x+3) + (2x+3) (5x - 4 ) C = ( 7x - 1 ) (4x-3) - (7x-1) (2x+5) D = (8x-1) - (2x-7) (8x-1) E = (4x-3) ² - (4x-3) (5x-7) F = (9 - 4x) - ( 9- 4x)²