Steply

Graph y = 3/2x - 2 using a table

Step by step, with the reason for every step · Graphing with a table · Algebra 1

Step by step

The question

Question: graph y = (3/2)x − 2 using a table of values.

y = 32x − 2

We pick some x values.

We work out y for each one.

Each x and y make a point.

1 Choose x values

The slope has 2 at the bottom.

So we pick x values that 2 goes into: −2, 0 and 2.

Then y comes out whole.

x = −2, 0, 2: 2 goes in

Two points make a line.

The third one checks them.

2 Work out y

Put x = −2 in.

We get y = −5.

x = −2: y = 32(−2) − 2 = −3 − 2 = −5
−5

Now x = 0 in.

We get y = −2.

x = 0: y = 32(0) − 2 = 0 − 2 = −2
−2

Now x = 2 in.

We get y = 1.

x = 2: y = 32(2) − 2 = 3 − 2 = 1
1

3 Plot the points

Draw the grid.

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

The first one is (−2, −5).

Put a dot.

Careful!

The x on top comes first, then the y under it: (−2, −5).

Many people write the y first.

Careful: not (−5, −2) ✗

(0, −2).

Dot.

(2, 1).

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 = 4.

We get y = 4.

x = 4: y = 32(4) − 2 = 6 − 2 = 4

The point (4, 4) 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
1

Your turn

Try this one yourself, then check:

y = 12x − 4
Show the answer
(−2, −5), (0, −4), (2, −3)

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