Linear Equation

Linear Equation An algebraic equation having the highest degree of the variable as one is known as a linear equation. A linear equation can be in one variable say x or it may have two variable say a, b. But in both the cases the highest degree of the variable in the linear equation is 1. A linear equation in two variables has its graph in the form of a straight line. Example 1: Which of the following equation is a linear equation? Support your answer by giving a suitable reason. a. x + 2y = 5 b. p2 3q + 7 = 0 Solution: For identifying a linear equation we need to recall the basic definition of linear equation. A linear equation is anequation with the variables having the highest degree as 1. So we check the highest degree of the variables in the givenequations. a. The highest degree is 1 for the variables x and y. So it is a linear equation. b. The highest degree is 2 which is the power of p. Thus it is not a linear equation. Example 2: Write whether the given graph is of a linear equation? Give reasons for your answer. Solution: a. As we already know that the graph of a linear equation is a straight line. In the given graph the curve is a straight line. This shows that the given graph is of a linear equation. b. The given graph is a parabola and not a straight line. This proves that this graph is not a linear equation.