(х+3-х^2/х+1):х+3/1-х^2
х+3-х^2/х+1*1-х^2/х+3
х+3-х^2/х+1*1^2-х^2/х+3
х+3-х^2/х+1*(1-х)*(1+х)/х+3
(х+3-х^2)*1-х/х+3
(х+3-х^2)*(1-х)/х+3
х-х*х+3-3х-х^2-х^2*(-х)/х+3
х-х^2+3-3х-х^2+х^3/х+3
1х-1х^2+3-3х-1х^2+х^3/х+3
(1-3)*(-1-1)х^2+3+х^3/х+3
-2х-2х^2+3+х^3/х+3.