=(X+2)/X(X+2)*X(X-2)方/(X+2)(X-2)-(X-1)/(X-2)方*X(X-2)方/(X+2)(X-2)
=(X-2)/(X+2)-X(X-1)/X+2)(X-2)
=(X方-4X+4-X方-X)/(X方-4)
=(4-5X)(X方-4)