One problem

[kate]

In the plain we have given point O(0;0) and line g whose equations is x - 3y - 3 = 0. Find the equation of the line l which passes through O and is perpendicular to g.

[Guest]

if the slope of the line is [tex]m[/tex], then the slope of a line perpendicular to it is [tex]\frac{-1}{m}[/tex]. So the slope of the new line will be [tex]\displaystyle\frac{-1}{\displaystyle\frac{1}{3}}=-3[/tex]. So the equation of the new line will be of the form [tex]y=-3x+c[/tex] and since it passes through [tex](0,0)[/tex], substituting the coordinate gives us [tex]c=0[/tex].

so the final equation is [tex]\boxed{y+3x=0}[/tex]