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.
The Cost of Uncompensated Care. Over 72 million nonelderly people were without insurance coverage for either the full year (40.8 million people) or for part of the year (31.4 million people) in 2013. On average, a person who is uninsured had considerably lower annual health care expenses than a person who is insured.