Fill in the Blank with One of the Words or Phrases

Multiple Choice

Fill in the blank with one of the words or phrases listed below. $$\begin{array} { l l l } \text { slope-intercept } & \text { directly } & \text { slope } \\\text { jointly } & \text { parallel } & \text { perpendicular } \\\text { function } & \text { inversely } & \text { linear function }\end{array}$$
-Two lines are--------------- if the product of the slopes is -1.

A) slope-intercept
B) perpendicular
C) parallel
D) jointly