Linear Equations Definitions Linear Equation - An equation involving variables of the first degree only (i.e., no quadratic (x 2 ) or cubic (x 3 ) terms). For example, 10x + 2 = 5x + 12 is a linear equation while x 2 + 4 = x - 5 is not a linear equation but is rather a quadratic equation. Solution - A number that, when substituted for the unknown, will make the equation true. For example, in the equation x + 3 = 4, the number 1 is the solution since 1 + 3 = 4 Examples of Linear and Non Linear Equations Linear Equations The following is a linear equation, even though it has two different variables. 5x + 7y = 14 The following is a system of linear equations, even though it has two different equations with two different variables in each equation. 10x + 15y = 72 22x + 3y = 102 Non Linear Equations The following are not linear equations since they have an exponent with a power that is not 1. x 2 - 2x + 1 = 0 x -5 + y -5 + 15...