<PRE><B>Question 249964</B>
4x + 3y = 5 
3y=-4x+5
y=-4x/3+5/3 (red line)
This line has a slope=-4/3
 3x - 4y = 10
-4y=-3x+10
y=-3x/-4+10/-4
y=3x/4-2.5 Green line)
This line has a slope=3/4 
Thus these 2 lines are perpendicular.
{{{ graph( 300, 300, -6, 5, -6, 5, -4x/3 +5/3, 3x/4 -2.5) }}} (graph 300x300 pixels, x from -6 to 5, y from -6 to 5, of TWO functions -4x/5 +5/3 and 3x/4 -2.5). </PRE>