Question 121922
Perpendicular lines have slopes that are negative reciprocals of each other.
In other words, 
{{{m[1]*m[2]=-1}}}
The product of the slopes is -1.
All of your equations are in slope-intercept form.
{{{y=mx+b}}}
and
{{{m[1]=4/7}}}
{{{m[2]=3}}}
{{{m[3]=-(1/3)}}}
{{{m[4]=1/3}}}
From your 4 choices, the answer is B and C since
{{{3*(-1/3)=-1}}}
Graphing the equations, you see they are perpendicular. 
 {{{ graph( 300, 300, -5, 5, -5, 5, 3x-4/7 
, -(1/3)x+4/7 ) }}}