Question 167200
Perpendicular to 3x-4y=9 and passing through (-2, -1)
4y=3x-9
y=3x/4-9/4 (red line)
This line has a slope(m)=3/4.
Any perpendicular line will have a slope(m)=-4/3.
Y=mX+b
-1=-4/3*-2+b
-1=8/3+b
b=-1-8/3
b=(-3-8)/3
b=-11/3
Thus the desired line equartion is:
y=-4x/3-11/3 (green line)
{{{ graph( 300, 300, -5, 5, -5, 5, 3x/4 -9/4, -4x/3 -11/3) }}} (graph 300x300 pixels, x from -5 to 5, y from -5 to 5, of TWO functions 3x/4 -9/4  and -4x/3 -11/3).