Steply

Graph y = -3/2x + 2

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

Step by step

The question

Question: graph y = −(3/2)x + 2.

y = −32x + 2

1 Read m and b

b is the number on its own: 2.

The line crosses the y-axis at 2.

That point is called the y-intercept.

b = 2 → start at 2

m is the number in front of x: −3/2.

It is the slope.

The bottom is the run: right 2.

The top is the rise: down 3.

m = −32 → right 2, down 3

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 2.

Put a dot.

3 Use the slope

From the dot, go right 2,

then down 3.

Put a dot.

Again: right 2,

down 3.

Dot.

We can also go back: left 2,

up 3.

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 = 2 and x = 4.

Put x = 2 in.

We get y = −1.

y = −32(2) + 2 = −3 + 2 = −1
−1

The point (2, −1) is on our line.

Now x = 4 in.

We get y = −4.

y = −32(4) + 2 = −6 + 2 = −4
−4

The point (4, −4) 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 = −32x + 2

Your turn

Try this one yourself, then check:

Graph y = −2x + 3
Show the answer
start at 3, right 1, down 2

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