Question

Which best describes the graphs of the line that passes through (−12, 15) and (4, −5), and the line that passes through (−8, −9) and (16, 21)?
A)
They are parallel lines.


B)
They are vertical lines.


C)
They are perpendicular lines.


D)
They are intersecting lines.

Answer 1

Answer:D) They are intersecting lines.

Step-by-step explanation: that other answer was wrong .

Answer 2

Answer:

C) They are perpendicular lines.

Step-by-step explanation:

We first need to find the slope of the graph of the lines passing through these points using:

$m = \frac{y_2-y_1}{x_2-x_1}$

The slope of the line that passes through (−12, 15) and (4, −5) is

$m_{1} = \frac{ - 5 - 15}{4 - - 12}$

$m_{1} = \frac{ - 20}{16} = - \frac{5}{4}$

The slope of the line going through (−8, −9) and (16, 21) is

$m_{2} = \frac{21 - - 9}{16 - - 8}$

$m_{2} = \frac{21 + 9}{16 + 8}$

$m_{2} = \frac{30}{24} = \frac{5}{4}$

The product of the two slopes is

$m_{1} \times m_{2} = - \frac{4}{5} \times \frac{5}{4} = - 1$

Since

$m_{1} \times m_{2} = - 1$

the two lines are perpendicular.