bonjour
A = 2 x + 7
B = 3 - x
C = ( 2 x - 5 ) / ( x + 1 )
B - C
= 2 x + 7 - ( 3 - x )
= 2 x + 7 - 3 + x
= 3 x + 4
C - 1 /A
= ( 2 x - 5 ) / ( x + 1 ) - 1 / ( 2 x + 7 )
= ( 2 x - 5 ) ( 2 x + 7 ) / ( x + 1 ) ( 2 x + 7 ) - [ 1 ( x + 1 ) / ( x + 1 ) ( 2 x + 7)]
= 2 x - 5 - 1
= 2 x - 6
