`Algebra`

P^

1

`10 Write the following as single fractions.`

(i) xx 4 +^1 + 2 –^1 (ii) 23 xx– 5 –^1 (iii) 35 xx 4 ––+ 67

`(iv) 32 ()xx 5 +^1 –^72 (– 2 ) (v) 41 xx 8 + +^7312 –`

`11 Simplify the following expressions.`

(i) 26 xx++^3 (ii) 62 1

32 1

`2`

5

##### ()

##### ()

`x`

x

##### +

##### +

`(iii)`

##### 23

##### 83

`4`

2

`xy`

xy

##### (– )

##### (– )

(iv) (^61) xx–– 22 (v) ()^32664

x^24

x

x

x

##### + ×

##### +

### Linear equations

●?^ What is a variable?

`You will often need to find the value of the variable in an expression in a`

particular case, as in the following example.

`EXAMPLE 1.13 A polygon is a closed figure whose sides are straight lines. Figure 1.1 shows a`

seven-sided polygon (a heptagon).

`An expression for S°, the sum of the angles of a polygon with n sides, is`

S = 180(n − 2).

`●?^ How is this expression obtained?`

Try dividing a polygon into triangles, starting from one vertex.

`Find the number of sides in a polygon with an angle sum of (i) 180° (ii) 1080°.`

`Figure 1.`