Question

What is the slope of line PQ?

Answer 1

we know that

The formula to calculate the slope between two points is equal to

$m=\frac{y2-y1}{x2-x1}$

Part a) Find the slope of line PQ

$P(-8,2)\ Q(4,2)$

substitute in the formula

$m=\frac{2-2}{4+8}$

$m=\frac{0}{12}=0$

Any line parallel to X-axis has slope equal to zero

so

the line PQ is parallel to the x-axis

therefore

the answer Part a) is

$0$

Part b) Find the slope of line MN

$M(8,6)\ N(8,-8)$

substitute in the formula

$m=\frac{-8-6}{8-8}$

$m=\frac{-14}{0}$

Anything divided by zero is undefined

m=undefined

therefore

the answer Part b) is

undefined

Part c) How are the two lines related ?

we know that

Any line perpendicular to X-axis has slope undefined

Because the term $(x2-x1)$ will always be zero

so

the answer Part c) is

the lines are perpendicular

Answer 2

The slope for PQ is 0.

The slope for MN is undefined.

The lines are perpendicular