If you're talking about inequality graphs, you shade the area where any point in the shaded area can solve the inequality, if I remember correctly. I can't exactly show you how much to shade.
X=40 degrees and y=40 degrees
No. In order to make the ratio correct you would need to divide both numbers of original recipe by the same number. 15/3=5 but 17/3 is not equal to 7
Postulate
For postulates, no evidence/proof is needed. It is always believed to be true.
