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Graph y = 1/2x + 1

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

Step by step

The question

Question: graph y = (1/2)x + 1.

y = 12x + 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: 1/2.

It is the slope.

The bottom is the run: right 2.

The top is the rise: up 1.

m = 12 → right 2, 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 1.

Put a dot.

3 Use the slope

From the dot, go right 2,

then up 1.

Put a dot.

Again: right 2,

up 1.

Dot.

We can also go back: left 2,

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 = 2 and x = 4.

Put x = 2 in.

We get y = 2.

y = 12(2) + 1 = 1 + 1 = 2
2

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

Now x = 4 in.

We get y = 3.

y = 12(4) + 1 = 2 + 1 = 3
3

The point (4, 3) 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 = 12x + 1

Your turn

Try this one yourself, then check:

y = 13x + 1
Show the answer
start at 1, right 3, up 1

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