How_To_Be_Good_At_Math

304 ALGEBRA •^ SOLVING EQUATIONS

Solving equations

An equation can be rearranged to find the value

of an unknown number, or variable.

Equations with symbols

Here we have two equations with

a shape representing the unknown

values. To find the answers we

simply multiply or divide.

Equations with letters

In these examples, letters are

used to represent the unknown values.

The equations are solved in the same

way. We just follow the maths sign.

It doesn’t matter whether a

shape or a letter represents

the variable.

Simple equations

In algebra, a letter or a symbol represents the variable.

We already know that the two sides of an equation

must always balance. So, if the variable is on its own

on one side of the equals sign, we can find its value by

simply carrying out the calculation on the other side.

Everyday algebra

We use algebra every

day without realizing it.

For example, if we want

to buy three bottles of

juice, two boxes of

cereal, and six apples,

we can calculate the

amount using an

algebraic equation

as shown here. We write the equation as:

3a + 2b + 6c = total cost.

Now replace the letters

with the prices as follows:

(3 × £2) + (2 × £1) + (6 × 50p) = £11

b = £1 c = 50p

a = £2

The letter represents

the unknown value

b^ = 8

a = 36 + 15 b = 21 − 13

a^ = 51

(^) = 84^ = 8
= 12 × 7 = 72 ÷ 9
The shape represents
the unknown value
c
ba
REAL WORLD MATHS
304-305_Solving_Simple-Equations.indd 304 29/02/2016 18:57