expressions

(have no equals sign)

equations

algebra

uses letters as symbols to represent a number

simplifying

(collecting like terms)

3b + b + 5 = 4b + 5

We don’t usually use x and ÷ symbols in expressions and equations

a + b

5 + 10a

4a

2a + 5b - 3c

a - 5

2a + 5 = 12

3a - 5 = 2

12 = a - b

4b = 16

a x a is written as a²

4 ÷ b is written as 4

5b x 3b = 15b²

12a⁴ = 2a³

**expanding brackets**

4a (2 + c) = 8a + 4ac

3y (y + 6) = 3y² + 18y

2 (4 - a) = 8 - 2a

be careful with negative numbers

-4 (c - 7) = -4c + 28

3 (-2a + 5) = -6a + 15

**substitution**

replacing a letter with a number

n + 8

if n = 12

n + 8 = 12 + 8 = 20

remember, brackets first, then x and ÷, then + and -

2 (a + 5)

if a = 11

2 (a + 5) = 2 x 16 = 32

2 + a²

if a = 10

2 + a² = 2 + 100 = 102

have an equals sign

_

b

__

6a

Before you watch, try these to see what you have remembered. Note your working out and answers on a piece of paper:

1. expand 2 (3b - 2)

2. expand 5a (2a + 7)

3. expand 2m (3 - m)

4. simplify 3a + 2a - b

5. simplify 4k - k + 2k

6. If n = 12, what is 3n - 5?

7. If c = 28, what is c + 74?

**You are going to use this prezi to revise**

expanding, simplifying and substituting

algebraic expressions and equations.

We have looked at this before, although some of the vocabulary was new, so it's OK if you have forgotten some of it.

expanding, simplifying and substituting

algebraic expressions and equations.

We have looked at this before, although some of the vocabulary was new, so it's OK if you have forgotten some of it.

**Don't worry if you got stuck. Work your way through this presentation for some reminders. You will get a chance to change your answers later if you want to!**

Now check your answers from the beginning of the prezi. Make any changes you want. Look back over the presentation again if you'd like.

If you have any questions, note them down so you can ask me in the lesson.

Here are the answers for you to check your work. If you made mistakes, try to work out where you went wrong. If you can't, then ask me about it in the lesson.

1. 6b-4 2. 10a²+35a 3. 6m-2m² 4. 5a-b 5. 5k 6. 31 7. 102