RD Sharma Solutions Class 9 Maths Chapter 13 Linear Equations … RD Sharma Solutions Class 9 Maths Chapter 13 Linear Equations in Two Variables are available here. This chapter deals with the study of linear equations with two variables. An equation is said to be a linear equation in two variables if it is written in the form of ax + by + c=0, where a, b & c are real numbers and the coefficients of x and y, i.e a and b respectively, are not equal to zero.