RD Sharma Solutions for Class 7 Chapter 8 “Linear Equation in One Variable”, A linear equation is an equation of a straight line, written in one variable. The only power of the variable is 1. Linear equations in one variable may take the form a x + b = 0 \ display style ax+b=0 ax+b=0 and are solved using basic algebraic operations. Chapter starting with definition, the solution to the linear equation, the definition of linear equation, systematic method of solving a linear equation, transposition method of solving a linear equation, trial and error method of solving a linear equation and finally applications of linear equations to practical problems.