x²+2（m-1）x+2m+6=01)b^2-4ac=4(m-1)^2-4(2m+6)>0 (m-5)(m+1)>0 m<-1 or m>52)f(0)>0 2m+6>0 m>-33)f(4)>0 16+2（m-1）4+2m+6>0 10m>-14 m>-7/5∴-7/5
