Steply

Graph y = x

Step by step, with the reason for every step · Graphing y = mx + b · Algebra 1

Step by step

The question

Question: graph y = x.

y = x

1 Read m and b

b is the number on its own: 0.

The line crosses the y-axis at 0.

That point is called the y-intercept.

b = 0 → start at 0

X means 1x, so m = 1.

It is the slope.

As a fraction: 1/1.

The bottom is the run: right 1.

The top is the rise: up 1.

m = 1 = 11 → right 1, up 1

2 Start at b

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.

Start on the y-axis at 0.

Put a dot.

3 Use the slope

From the dot, go right 1,

then up 1.

Put a dot.

Again: right 1,

up 1.

Dot.

We can also go back: left 1,

down 1.

Dot.

4 Draw the line

Join the dots with a straight line.

It keeps going both ways.

5 Check

Let's check with a table.

We pick x = 1 and x = 2.

Put x = 1 in.

We get y = 1.

y = 1
1

The point (1, 1) is on our line.

Now x = 2 in.

We get y = 2.

y = 2
2

The point (2, 2) is on our line.

Both points are on the line.

So the graph is right!

Let's look back.

First: read m and b.

Then: start at b.

Then: use the slope.

Then: draw the line.

Last: check.

Answer
y = x

Your turn

Try this one yourself, then check:

Graph y = 2x
Show the answer
start at 0, right 1, up 2

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