Question 45125
Equation of a line through a givin point (a,b) and having slope m i.e. tan∂ = m is given by :

y-b = m(x-a) .......... (1)

In the given problem we have the values as :

m = 6
a = 0
b = 9

substituting in (1) above, we get

y-9 = 6(x-0)
or
y-9 = 6x

or 

6x-y+9 = 0  ........... (2)

This is the required equation to the line.

Here the only trick was to remember the equation which represents a straight line passing through a given point & having a certain slope.