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Are -(x - 6) and -x - 6 equivalent

Step by step, with the reason for every step · Equivalent expressions · Algebra 1

Step by step

The question

Question: are −(x − 6) and −x − 6 equivalent?

−(x − 6) and −x − 6

Equivalent means: the two are equal, whatever number the letter is.

equivalent = equal for every number

First we simplify the first one: −(x − 6).

We write it shorter, with the same value.

= −(x − 6)

1 Open the brackets

A minus in front of a bracket changes the sign of every part inside.

−( + ) → −, −( − ) → +

Now we have −x + 6.

= −x + 6

2 Compare

−x + 6 and −x − 6 are not the same.

= −x + 6 ≠ −x − 6

So no: they are not equivalent.

= no: not equivalent

3 Check

Let's check with a number: x = 2.

The first gives 4.

The second gives −8.

Different.

So the answer is right!

x = 2: −(2 − 6) = 4, −2 − 6 = −8

Let's look back.

First: open the brackets.

Then: compare.

Last: check.

Answer
= no: not equivalent

Your turn

Try this one yourself, then check:

Are −(x − 9) and −x − 3
Show the answer
no, not equivalent

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