Question

因式分解习题：a的平方减去9a如何分解成含有a-1的因式分解

Answer 1

sina+根号3cosx
=根号[1^2+(根号3)^2]*sin(a+x)
=2sin(a+x)
其中tanx=根号3
-1<=sin(a+x)<=1

所以-2<=(4m-6)/(4-m)<=2

-2<=(4m-6)/(4-m)
(4m-6)/(4-m)+2>=0
(4m-6+8-2m)/(4-m)>=0
(2m+2)/(4-m)>=0
(2m+2)(4-m)>=0
(2m+2)(m-4)<=0
-1<=m<=4,分母不等于0
-1<=m<4

(4m-6)/(4-m)<=2
(4m-6)/(4-m)-2<=0
(4m-6-8+2m)/(4-m)<=0
(6m-14)(4-m)<=0
(6m-14)(m-4)>=0
m<=7/3,m>=4分母不等于0
m<=7/3,m>4

所以
-1<=x<=7/3

Answer 2

不可能的
a²-9a=a(a-9)
没有a-1