Question

3≤|8-x| |x+1|>2-x |x+3|7|x+1| x^2-6|x|+9>0 |x-1|+|x+2|≥5

Answer 1

3≤|8-x|

平方得：

x^2-16x+55≥0

(x-5)(x-11)≥0

x≥11,x≤5

|x+1|>2-x 分类

当x>-1时,x+1>2-x,x>1/2

当x1/2

|x+3|