2x+9y=-30 subtract 2x from both sides
9y=-2x-30 divide both sides by 9
y=-2x/9-30/9
So the slope of the reference line is -2/9. For a line to be perpendicular to this line their slopes must be negative reciprocals of one another, mathematically:
m1*m2=-1 and in this case:
-2m/9=-1
m=9/2
m=4.5, so far we have:
y=4.5x+b, using point (-8, 0) we can solve for b
0=4.5(-8)+b
0=-36+b
36=b, so our line is:
y=4.5x+36