Steply

Are x = 3 and y = -2 parallel, perpendicular or neither

Step by step, with the reason for every step · Parallel and perpendicular lines · Algebra 1

Step by step

The question

Question: are x = 3 and y = −2 parallel, perpendicular or neither.

① x = 3 and ② y = −2

The slopes tell us which.

Same slope: parallel.

Flip the slope and change its sign: perpendicular.

parallel: same slope
perpendicular: flip and change the sign

1 Slope of ①

x = 3 is a vertical line: straight up and down.

We call its slope undefined.

m1 = undefined

2 Slope of ②

There is no x term.

So m = 0: a flat line.

b is −2.

m2 = 0
b = −2

3 Compare the slopes

One line is vertical, the other is flat.

A vertical line and a flat line always meet at a square corner.

undefined and 0

So the lines are perpendicular: they meet at a square corner.

① and ② are perpendicular

4 Check

Let's see it on the grid.

Draw both lines.

They meet at a square corner.

Let's look back.

First: slope of ①.

Then: slope of ②.

Then: compare the slopes.

Last: check.

Answer
① and ② are perpendicular

Your turn

Try this one yourself, then check:

Are ① x = −1 and ② y = 4
Show the answer
perpendicular

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