Determine which of the lines $L _ { 1 } , L _ { 2 }$ and $L _ { 3 }$ passing through the indicated pairs of points are parallel.
$\begin{array} { |l|l|}
\hline L _ { 1 } & ( - 2 , - 7 ) , ( 0,1 )\
\hline{ L _ { 2 } }&(-2,11),(5,-24) \
\hline{ L _ { 3 } } &(0,-2),(5,18)\
\hline
\end{array}$
A) $L _ { 1 } \text { and } L _ { 3 }$
B) $L _ { 1 } \text { and } L _ { 2 }$
C) $L _ { 2 } \text { and } L _ { 3 }$
D)all are parallel
E)none are parallel

Question

Determine which of the lines $L _ { 1 } , L _ { 2 }$ and $L _ { 3 }$ passing through the indicated pairs of points are parallel. 
$\begin{array} { |l|l|} 
\hline L _ { 1 } & ( - 2 , - 7 ) , ( 0,1 )\
\hline{ L _ { 2 } }&(-2,11),(5,-24) \
\hline{ L _ { 3 } } &(0,-2),(5,18)\
\hline
\end{array}$
A) $L _ { 1 } \text { and } L _ { 3 }$
B) $L _ { 1 } \text { and } L _ { 2 }$
C) $L _ { 2 } \text { and } L _ { 3 }$
D)all are parallel
E)none are parallel

Quizplus · Accepted Answer

The slopes of the lines are calculated as follows:  $L_1$: $\frac{1 - (-7)}{0 - (-2)} = \frac{8}{2} = 4$  $L_2$: $\frac{-24 - 11}{5 - (-2)} = \frac{-35}{7} = -5$  $L_3$: $\frac{18 - (-2)}{5 - 0} = \frac{20}{5} = 4$  Since $L_1$ and $L_3$ have the same slope, they are parallel.

Determine Which of the Lines L1,L2L _ { 1 } , L _ { 2 }L1​,L2​

Determine Which of the Lines $L _ { 1 } , L _ { 2 }$