Graph y = -x - 1 using a table Step by Step

Step by step

The question

Question: graph y = −x − 1 using a table of values.

y = −x − 1

We pick some x values.

We work out y for each one.

Each x and y make a point.

1 Choose x values

We pick three easy x values: −1, 0 and 1.

Two points make a line.

The third one checks them.

2 Work out y

Put x = −1 in.

We get y = 0.

x = −1: y = −(−1) − 1 = 1 − 1 = 0

Careful!

Minus times minus is plus.

−1 × (−1) is 1, not −1.

Careful: not −1 × (−1) = −1 ✗

Now x = 0 in.

We get y = −1.

x = 0: y = −(0) − 1 = 0 − 1 = −1

−1

Now x = 1 in.

We get y = −2.

x = 1: y = −1 − 1 = −2

−2

3 Plot the points

Draw the grid.

Each column is a point: x on top, y under it.

The first one is (−1, 0).

Put a dot.

(0, −1).

Dot.

(1, −2).

Dot.

4 Draw the line

The three dots line up.

Join the dots with a straight line.

It keeps going both ways.

5 Check

Let's check with one more x: x = 2.

We get y = −3.

x = 2: y = −2 − 1 = −3

The point (2, −3) is on our line.

So the graph is right!

Let's look back.

First: choose x values.

Then: work out y.

Then: plot the points.

Then: draw the line.

Last: check.

Answer

−2

Graph y = -x - 1 using a table