Steply

Graph y = (x + 1)^2 + 4 from y = x^2

Step by step, with the reason for every step · Graph transformations · Algebra 2

Step by step

The question

Question: graph y = (x + 1)² + 4 from y = x².

y = (x + 1)2 + 4

We know the graph of y = x².

It is a U, with its turning point at (0, 0).

we know: y = x²

1 Read the changes

Inside, next to x, we have + 1.

x = −1 makes the inside 0.

So the turning point moves to x = −1: left 1.

x + 1 inside → left 1

Careful!

Inside, it goes the opposite way to the sign.

Careful: + 1 inside goes left, not right

Outside, at the end, + 4 adds 4 to every y.

So the graph moves up 4.

+ 4 outside → up 4

2 Start from y = x²

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.

Draw y = x² first.

Its turning point is at (0, 0).

3 Move the turning point

Move it left 1.

Then up 4.

The new turning point is (−1, 4).

4 Draw the new graph

The shape stays the same.

From the turning point, 1 right, 1 up.

And 1 left, 1 up.

Join them with the same U.

This is y = (x + 1)² + 4.

5 Check

Let's check.

Put x = −1 in the new rule.

We get y = 4: the turning point (−1, 4).

x = −1: y = (−1 + 1)2 + 4 = (0)2 + 4 = 0 + 4
= 4

And x = 0 gives y = 5: the point (0, 5) we drew.

x = 0: y = (0 + 1)2 + 4 = (1)2 + 4 = 1 + 4
= 5

Let's look back.

First: read the changes.

Then: start from y = x².

Then: move the turning point.

Then: draw the new graph.

Last: check.

Answer
+ 4 outside → up 4

Your turn

Try this one yourself, then check:

graph y = (x + 1)2 + 2 from y = x²
Show the answer
turning point (−1, 2)

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