Question

The slope of the line that goes through -3, -5 and -3, -6 is
a. positive
b. negative
c. zero
d. undefined
i dont understand can someone help

Answer 1

Note that (-3,5) and (-3,6) lie on the same vertical line.
the slope is ∆y/∆x but since x does not change, ∆x=0, and division by zero is undefined.
horizontal lines have slope zero, but the slope of vertical lines is undefined.