I do not understand this

Step-by-step explanation:

The first question's slope is 0 because it is a straight horizontal lineThe second question is undefined because it is a straight vertical lineThe third question's slope isn't able to be found with a blank line, but the line is positive because the more it travels right, it also goes up. So the slope of the third is positiveThe fourth is similar to the third as its slope cannot be calculated with a blank line, but the more it moves right, the more it moves down, meaning the slope is negative.

Answer: 900°

good luck on your studies! : )

david edward.