1. Background Knowledge By the end of this lesson you will be able to explain/solve the following: 1.The Subject of an equation 2.Rearrange a given formula

2. Formula Rearrangement D = xt + p D In the formula D = xt + p we say that D is the subject. D x, t p This is because D is expressed in terms of the other variables x, t and p. We can rearrange the formula to make one of the other variables the subject. We do this using the usual rules for solving equations. Whatever we do to one side of the equation we must also do to the other side.

3. Worked Example 18

4. Exercise I

5. Worked Example 19

6. Exercise I

7. Worked Example 20

8. Exercise I