bonjour
x(5x+3)+x(2x+7) = x ( 5 x + 3 + 2 x + 7 ) = x ( 7 x + 10 )
100(13x- 8) - 100(7x- 4) = 100 ( 13 x - 8 - 7 x + 4 ) = 100 ( 6 x - 4 )
(x+3)(2x- 1)+(x+3)(8x+5) = ( x + 3 ) ( 2 x - 1 + 8 x + 5 ) = ( x + 3 ) ( 10 x + 4 )
5x(3x- 4)- (3x- 4) (9x- 1) = ( 3 x - 4 ) ( 5 x - 9 x + 1 ) = ( 3 x - 4 ) ( - 4 x + 1 )