
x1+x2=3-m得(x1+x2)²=(3-m)²
x1*x2=m
(x1-x2)²=(x1+x2)²-4x1*x2
=(3-m)²-4m
=m²-10m+9
∵二根差绝对值小于2√5
∴0≤m²-10m+9≤20
解得-1≤m≤1或9≤m≤11
x^2+(m-3)x+m=0
x1=(3-m+sqrt((m-3)^2-4m)/2
x2=(3-m-sqrt((m-3)^2-4m)/2
x1-x2=sqrt((m-3)^2-4m)<2*sqrt(5)
m^2-10m+9<20
m^2-10m-11<0
-1
(m-3)^2-4m>=0
m^2-10m+9>=0
m>=9或m<=1
因此 -1
由方程关系可得,两实数和=(3-m)两实数积=m
所以,代入可得
解不等式得
m大于-1小于11