-1 = -18 + b
b = -1+18 = 17
Your equation is y = -3x + 17
2. Parallel to the x axis means no slope at all (or a 0 slope)
Since you want a line below the axis, any equation of the form y = -k would do. (Where k is a positive real number)
3. X varies directly means that it's a linear equation where b=0 (form y = mx)
You solve like in number 1:
22 = m*6
m = 22/6 = 3,66666
4. First, treat it as a normal equation and isolate y:
2x-3y = 6
-3y = 6 - 2x
y = (6-2x)/(-3)
y = 2/3*x - 2
You then have your curve.
Then do a test. Take a value under the curve (e.g. (0,-3)) and see if the condition is respected:
2(0)-3(-3)=9 > 6, so the solution is not downwards of the curve.
Hence, it is upwards.
edit: note that the curve for the inequality is dotted, and not full.