Numerical : Write the equation of the line through the points ( 1 , – 1 ) and ( 3 , 5 ).
Solution : Here x1 = 1 , y1 = – 1 , x2 = 3 and y2 = 5 . Using two-point form formula
We get , y- ( -1 ) = ( 5 –( -1 ))/( 3 -1 ) * ( x- 1 ) or −3x + y + 4 = 0
Slope Intercept form
If slope & intercept on y axis is known for a line , we can form equation of the line .
Equation of line will be : y = mx + c