Revise of Important Concept – Straight Line


(A) Equation of a straight Line 

 An equation of straight line is given by y = mx + c.
The variables x and y are linearly related
The term c is known as y-intercept. It represents the y value where the line cuts the y-axis
The term m is the gradient of the straight line and its value is constant



(B) Gradient of a Straight Line
If the points A ( x 1 , y 1 )  and B ( x 2 , y 2 )   lie on the straight line y = m x + c , then gradient of ,the straight line
m = y 2 y 1 x 2 x 1 o r y 1 y 2 x 1 x 2



(C) Mid Point 



Mid Point AB is given by M = ( x 1 + x 2 2 , y 1 + y 2 2 )


(D) Distance Between Two Points
Distance between point A ( x 1 , y 1 ) and point is B ( x 2 , y 2 ) given by ( x 1 x 2 ) 2 + ( y 1 y 2 ) 2