Question to Find Equation of Line Passing through a Point

Topic : Equation of Line

Question : Find the equation of line passing through points (0,-1) given perpendicular to the line x + 3y = 4.

Solution :
An equation of the line through the point (0,-1) is perpendicular to the line x + 3y = 4, So
the slopes of the two perpendicular lines follow the relation m1 * m2 = -1
where m1 and m2 are the slopes of lines
m1 = - 1/3 (slope of x + 3y = 4)
m2 = ?
m1 * m2 = -1
-1/3 *m2 = -1
m2 = 3
So the required line will be having slope 3
(y - y1) = m (x - x1)
(y+1) = 3(x-0)
y + 1 = 3x
3x - y = 1