Determine whether the lines associated with the functions are parallel, perpendicular, or neither.
-$$\begin{array} { l }
f ( x ) = 9 x - 1 \
f ( x ) = - \frac { 1 } { 9 } x - 2
\end{array}$$
A) Neither
B) Perpendicular
C) Parallel

Question

Determine whether the lines associated with the functions are parallel, perpendicular, or neither.
-$$\begin{array} { l } 
f ( x ) = 9 x - 1 \
f ( x ) = - \frac { 1 } { 9 } x - 2
\end{array}$$
A) Neither
B) Perpendicular
C) Parallel

Quizplus · Accepted Answer

To determine whether the lines are parallel or perpendicular, we need to look at the slopes of the two lines.

The slope of the first line, $f(x) = 9x -1$, is 9.

The slope of the second line, $f(x) = -\frac{1}{9}x - 2$, is $-\frac{1}{9}$.

Two lines are perpendicular if and only if the product of their slopes is -1.

$9\cdot(-\frac{1}{9})=-1$

Since the product of the slopes is -1, the lines are perpendicular. Therefore, the answer is B.

Determine Whether the Lines Associated with the Functions Are Parallel f(x)=9x−1f(x)=−19x−2\begin{array} { l } f ( x ) = 9 x - 1 \\f ( x ) = - \frac { 1 } { 9 } x - 2\end{array}f(x)=9x−1f(x)=−91​x−2​

Determine Whether the Lines Associated with the Functions Are Parallel $\begin{array} { l } f ( x ) = 9 x - 1 \\f ( x ) = - \frac { 1 } { 9 } x - 2\end{array}$