Steply

Graph y = 3/4x - 2

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

Step by step

The question

Question: graph y = (3/4)x − 2.

y = 34x − 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: 3/4.

It is the slope.

The bottom is the run: right 4.

The top is the rise: up 3.

m = 34 → right 4, up 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 4,

then up 3.

Put a dot.

Again: right 4,

up 3.

Dot.

We can also go back: left 4,

down 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 = 4 and x = 8.

Put x = 4 in.

We get y = 1.

y = 34(4) − 2 = 3 − 2 = 1
1

The point (4, 1) is on our line.

Now x = 8 in.

We get y = 4.

y = 34(8) − 2 = 6 − 2 = 4
4

The point (8, 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 = 34x − 2

Your turn

Try this one yourself, then check:

y = 23x − 3
Show the answer
start at −3, right 3, up 2

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