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Domain of f(x) = 1/x + 5

Step by step, with the reason for every step · Domain and range · Algebra 2

Step by step

The question

Question: find the domain of f(x) = 1/x, + 5.

f(x) = 1x + 5

The domain is all the x's we can put in.

domain = the x's that can go in

1 Find where the bottom is 0

We can never divide by 0.

So the bottom can never be 0.

÷ 0: not allowed

The bottom is just x.

So x = 0 makes it 0.

x = 0

So the domain is all real numbers except 0: x ≠ 0.

x ≠ 0

2 See it on the graph

Draw the grid.

Here is the graph of f(x) = 1/x, + 5.

It never touches x = 0: that x can't go in.

3 Check

Let's check.

Put 0 in: the bottom is 0.

Not allowed.

x = 0: 10 = 10 not allowed

Let's look back.

First: find where the bottom is 0.

Then: see it on the graph.

Last: check.

Answer
x ≠ 0

Your turn

Try this one yourself, then check:

domain of f(x) = 3x + 3
Show the answer
domain: x ≠ 0

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