Question 249928
4x + 3y +5
3y=-4x=5
y=-4x/3+5/3 slope=-4/3 (red line) 
3x -4y = 10
-4y=-3x+10
y=-3x/-4+10/-4
y=3x/4-2.5 slope=3/4 (green line.
Because the slopes are negative recipricals of each other these lines are perpendicular.
{{{ graph( 200, 200, -6, 5, -6, 5, -4x/3 +5/3, 3x/4 -2.5) }}} (graph 200x200 pixels, x from -6 to 5, y from -6 to 5, of TWO functions -4x/3 +5/3 and 3x/4 -2.5).