The major thing that differentiate microeconomics from macroeconomics is the object of study. Microeconomics refers to the study of economics at individual, group or business level while macroeconomics involves the study of economics on the national scale, that is the study of the economy of a nation. The economics of a nation is the combination of all the individuals, businesses, households, etc in a country.
3x-3 and 4x-6 are complementary angles meaning together they add up to 180°. Set them equal to each other. So you get 3x-3=4x-6 now simplify this. Now you have x=3 and there you have it! If you plug 3 into x in both equations it works! Hope this helps!
Another name for a relation is a function.