Please help me. I do not understand this at all

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

2x minus y equals 6, x plus y equals negative 3

The number of calories you burn depends on your weight. a 110-pound person burns 163 calories during 30 minutes of tennis. find the number of calories that a 190-pound person would burn during the same activity, assuming they burn calories at the same rate.