PLS HLEP IVE BEEN ASKING AND NO ONE HELPS I BEG YOU

Which term best describes the association between variables a and b

An equation where variables are used to represent known values—function notation true or false

Atrain leaves little? rock, arkansas, and travels north at 90 kilometers per hour. another train leaves at the same time and travels south at 80 kilometers per hour. how long will it take before they are 680 kilometers? apart?