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Are 4(n - 2) and 4n - 2 equivalent

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

Step by step

The question

Question: are 4(n − 2) and 4n − 2 equivalent?

4(n − 2) and 4n − 2

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

equivalent = equal for every number

First we simplify the first one: 4(n − 2).

We write it shorter, with the same value.

= 4(n − 2)

1 Open the brackets

The 4 in front of the bracket multiplies every part inside.

a(b + c) = ab + ac

So we write 4 times each part.

= 4(n) + 4(−2)
− × + = −

Watch the signs.

4 times n is 4n.

4 times (−2) is −8.

= 4n − 8

2 Compare

4n − 8 and 4n − 2 are not the same.

= 4n − 8 ≠ 4n − 2

Careful!

The 4 multiplies both parts in the bracket, the 2 too.

Careful: not 4(n − 2) = 4n − 2 ✗

So no: they are not equivalent.

= no: not equivalent

3 Check

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

The first gives 0.

The second gives 6.

Different.

So the answer is right!

n = 2: 4(2 − 2) = 0, 4(2) − 2 = 6

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 6(n − 9) and 6n − 48
Show the answer
no, not equivalent

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