Steply

Graph y < 3

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

Step by step

The question

Question: graph y < 3.

y < 3

The answer is not one point.

It is every point that makes this true.

That is a whole part of the grid.

answer = all the points that work

1 Draw the line

First we draw the line where both sides are equal: y = 3.

y = 3

The sign is less than, with no "or equal to".

So points on the line are not answers.

We draw it dashed, like the open circle on a number line.

< → dashed line

Draw the grid.

The x-axis goes across.

The y-axis goes up and down.

They meet at 0.

That point is called the origin.

b = 3.

Start on the y-axis at 3.

A flat line through the dot: dashed.

2 Test a point

The line cuts the grid in two sides.

One side is the answer.

We test one point: (0, 0).

Zeros are easy to work with.

Put x = 0 and y = 0 in.

0 < 3 true

Is 0 less than 3?

Yes, that is true.

So (0, 0) is an answer.

3 Shade

So we shade the side with (0, 0).

Every point there is an answer.

4 Check

Let's check with a point in the shaded part: (−2, −1).

Put x = −2 and y = −1 in.

−1 < 3 true

True!

So the shading is right.

Let's look back.

First: draw the line.

Then: test a point.

Then: shade.

Last: check.

Answer
0 < 3 true

Your turn

Try this one yourself, then check:

Graph y < 2
Show the answer
dashed line y = 2, shade below

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