Algebra is used in Maths when we do not know ... We have to include their first month as x = 0, so their 2nd month will be x = 1. Now we know x = 1, we can substitute it into y = 12 + 8x.

In algebra, letters are used to stand for values that can change (variables) or for values that are not known (unknowns). A term is a number or letter on its own, or numbers and letters multiplied ...