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.
Health Insurance. An out-of-network provider is one which has not contracted with your insurance company for reimbursement at a negotiated rate. Some health plans, like HMOs, do not reimburse out-of-network providers at all, which means that as the patient, you would be responsible for the full amount charged by your doctor.