Slacks implies pants of certain materials which are not part of a suit (jeans are not slacks, and you would not refer to the pair of trousers that came with a suit as slacks.) It is also more common to use slacks to refer to pants worn by women, while men would wear trousers.
Health care safety net providers are those that have a legal mandate or mission to offer medical care to all patients, regardless of their ability to pay, and have a substantial number of patients who are uninsured or on Medicaid.
Low-income working families make up over 40% of the remaining uninsured. Reflecting income and the availability of public coverage, people who live in the South or West are more likely to be uninsured. Most who remain uninsured have been without coverage for long periods of time.