Steply

Graph y = -4/3x + 1

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

Step by step

The question

Question: graph y = −(4/3)x + 1.

y = −43x + 1

1 Read m and b

b is the number on its own: 1.

The line crosses the y-axis at 1.

That point is called the y-intercept.

b = 1 → start at 1

m is the number in front of x: −4/3.

It is the slope.

The bottom is the run: right 3.

The top is the rise: down 4.

m = −43 → right 3, down 4

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 1.

Put a dot.

3 Use the slope

From the dot, go right 3,

then down 4.

Put a dot.

Again: right 3,

down 4.

Dot.

We can also go back: left 3,

up 4.

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 = 3 and x = 6.

Put x = 3 in.

We get y = −3.

y = −43(3) + 1 = −4 + 1 = −3
−3

The point (3, −3) is on our line.

Now x = 6 in.

We get y = −7.

y = −43(6) + 1 = −8 + 1 = −7
−7

The point (6, −7) 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 = −43x + 1

Your turn

Try this one yourself, then check:

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

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