The equation of the perpendicular line is given as
[tex]y=3x+\text{?}[/tex]It goes through the point (4, 2). Lets substitute and find the equation.
[tex]\begin{gathered} y=3x+\text{?} \\ 2=3(4)+\text{?} \\ 2=12+\text{?} \\ So,\text{ ?=-10} \\ \\ \text{Equation of Line} \\ y=3x-10 \end{gathered}[/tex]Answery = 3x - 10