### Linear Equations in Two Variables

Linear equations in two variables
A common form of a linear equation in the two variables

where

Since terms of linear equations cannot contain products of distinct or equal variables, nor any power (other than 1) or other function of a variable, equations involving terms such as

Forms for 2D linear equations Linear equations can be rewritten using the laws of elementary algebra into several different forms. These equations are often referred to as the "equations of the straight line." In what follows,

*x*and*y*iswhere

*m*and*b*designate constants (parameters). The origin of the name "linear" comes from the fact that the set of solutions of such an equation forms a straight line in the plane. In this particular equation, the constant*m*determines the slope or gradient of that line, and the constant term*b*determines the point at which the line crosses the*y*-axis, otherwise known as the y-intercept.Since terms of linear equations cannot contain products of distinct or equal variables, nor any power (other than 1) or other function of a variable, equations involving terms such as

*xy*,*x*2,*y*1/3, and sin(*x*) are*nonlinear*.Forms for 2D linear equations Linear equations can be rewritten using the laws of elementary algebra into several different forms. These equations are often referred to as the "equations of the straight line." In what follows,

*x*,*y*,*t*, and*θ*are variables; o…