|x+1|/|x+3|≥1
|x+1|≥|x+3|
(x+1)²≥(x+3)²
x²+2x+1≥x²+6x+9
4x≤-8
x≤-2
又|x+3|≠0,∴x≠-3
∴解集是：{x|x≤-2且x≠-3}