Bonsoir,
A=
(x*x)/ x +1/x = (x²+1)/x
B=
3( x+1)/(x+1) + 4/(x+1) = (3x+3 +4)/ (x+1) = (3x+7) / (x+1)
C=
x(x+1)/ (x+1) -x²/ (x+1) =
(x² +x -x²)/ (x+1)=
x/ (x+1)
