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Simplify (5x + 2) - (3x + 1)

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

Step by step

The question

Question: simplify (5x + 2) − (3x + 1).

Simplify means: write it shorter, with the same value.

(5x + 2) − (3x + 1)

1 Open the brackets

A bracket with a plus or nothing in front can just be removed.

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

−( + ) → −, −( − ) → +

Now we have 5x + 2 − 3x − 1.

= 5x + 2 − 3x − 1

2 Group like terms

Terms are the parts between the + and − signs.

Like terms are the same kind: same letters, same powers.

All the x terms go together.

Plain numbers go together.

Each colour is one kind.

like terms = same letters,
same powers

We move like terms next to each other.

Each term takes its sign with it.

= 5x − 3x + 2 − 1

5x − 3x is 2x.

It is like 5 apples take away 3 apples: that is 2 apples.

2 − 1 is 1.

5x − 3x = 2x
2 − 1 = 1

So the expression is 2x + 1.

= 2x + 1

3 Check

Let's check.

We pick a number for each letter: x = 2.

We put it into the start.

Start: (5 × 2 + 2) − (3 × 2 + 1) = 12 − 7
= 5

Now into our answer.

Answer: 2 × 2 + 1 = 4 + 1 = 5

Both give 5.

Same value, so 2x + 1 is right!

Both give 5

Let's look back.

First: open the brackets.

Then: group like terms.

Last: check.

Answer
= 2x + 1

Your turn

Try this one yourself, then check:

Simplify (6x + 2) − (3x + 1)
Show the answer
3x + 1

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