Bonsoir
(4-x)(2x-2) +( x-1)
(4-x)(2)(x-1) + (x-1)
(8-2x)(x-1) + (x-1) ( x-1) facteur commun
(x-1)( 8-2x + 1)
(x-1)( 9-2x)
( 4/3 - 8/7 ) / (5/2 - 1/3 )
on procède en deux temps
4/3 - 8/7 = 28 / 21 - 24/21 = 4/21
5/2 - 1/3 = 15/6 - 2/6 = 13/6 alors
(4/21) / (13/6) = (4/21) * ( 6/13) = 24/273
