①a & gt； b & gt0 & gtc & lt= = = & gta & gt-(a+c)>0 & gtc = = = >； 1 & gt； - 1-(c/a)>0 & gtc/a = = = & gt； -2 & lt； c/a & lt； - 1
②a & gt； 0 & gtb & gtc & lt= = = & gta & gt0 & gt-(a+c)>c = = = >； 1 & gt； 0 & gt- 1-(c/a)>c/a = = = & gt； - 1 & lt； c/a & lt； - 1/2
③a & gt； b = 0 & gtc & lt= = = & gta & gt-(a+c)= 0 & gt； c = = = >； 1 & gt； 0≥- 1-(c/a)>c/a = = = & gt； c/a=- 1
To sum up, the range of c/a is (-2,-1/2).
2. There is something wrong with the topic.
3. choose B.
Move the one to the right of B to get a3+B3-a2-a2≥0.
left = a(a2-B2)+B2(b-a)= a(a-b)(a+b)-B2(a-b)=(a-b)(a2+a b-B2)
When a>b is greater than 0, when a