9. The following shaded region is defined by the three inequalities
x > 0
y < 0
18x - 8y < 45

Nope, First subtract 18x from both sides of the equation: -8y < 45 - 18x
Then divide both sides by -8 (but remember that when you multiply or divide by a negative number, you need to flip the inequality sign):
    (-8/-8)y > {45/(-8)} -{18x/(-8)}
    y > -5.625 - (-2.25x)
    y > -5.625 + 2.25x (minus a minus same as plus a plus)
Whenever the inequality is "y >" it is an outside constraint. Which means the area above the line is shaded. However, choice a shows an inside constraint (shaded below the line).