## Chapter 2

## The Straight Line

##### 2.1 INTRODUCTION

In the previous chapter, we defined that the locus of a point is the path traced out by a moving point according to some geometrical law. We know that the locus of a point which moves in such a way that its distance from a fixed point is always constant.

#### 2.1.1 Determination of the General Equation of a Straight Line

Suppose the point *P*(*x, y*) moves such that *P*(*x, y*), *A*(4, −1), and *B*(2, 3) form a straight line. Then,

⇒ *x*(−4) − *y*(2) + 14 = 0

(i.e.) 4*x* + 2*y* − 14 = 0 or 2*x* + *y* − 7 = 0, which is a first degree equation in *x* and *y* that represents a straight line.

The general equation of a straight line ...