(1) What is degree of an equation?; (2) What are variables?; (3) What is a linear equation?; (4) How to understand a linear equation in multiple variables? (i) A linear equation in one variable, (ii) A linear equation in two variables, (iii) A linear equation in three variables; (5) Characteristics of a pair of linear equations; (6) Methods for solving a pair of linear equations in two variables, (i) Graphical method, (ii) Substitution method, (iii) Elimination method, (iv) Cross-multiplication method.
