Question

What is a straight line?

Answer 1

A line is simply an object in geometry that is characterized as a straight, thin, one-dimensional, zero width object that extends on both sides to infinity.
A straight line is essentially just a line with no curves.
We can also say that any line passing through two particular points in the same plane will be unique.
The general equation of a straight line can be written in following ways:
i) The Equation of a Line Using Slope-intercept
The equation of a line which has slope m and which has its y-intercept given as the distance c:
$m=\frac{(y-c)}{x}$
$mx=y–c$
y = mx + c is the equation of the line.
ii) The equation of a line passing through any given point and having a given slope
If $(x_1,y_1)$ be a point through which the line passes and its slope is m, then the equation of the line would be:
The equation of a line which has slope of the line m and which passes through the point $(x_1,y_1)$ is:
$m=\frac{(y-y_1)}{(x-x_1)}$
$y-y_1=m(x-x_1)$ is the equation of the line.