Determine whether the slope of the given line in ​(a)​-​(d) is​ positive, negative,​ zero, or undefined.

Question

​(a)

x
y
​(b)

x
y
​(c)

x
y
​(d)

x
y

Answer 1

(a) The slope is undefined in this case because the line is vertical.

(b) The slope is zero in this case because the line is horizontal.

(c) The slope is positive in this case because the line is increasing from left to right.

(d) The slope is negative in this case because the line is decreasing from left to right.