ABSTRACT
At the end of this chapter, you should be able to:
• understand basic operations in algebra • add, subtract, multiply and divide using letters instead of numbers • state the laws of indices in letters instead of numbers • simplify algebraic expressions using the laws of indices
We are already familiar with evaluating formulae using a calculator from Chapter 4. For example, if the length of a football pitch is L and its width is b, then the formula for the area A is given by
A = L × b This is an algebraic equation. If L = 120m and b = 60m, then the area A = 120× 60 = 7200m2
The total resistance, RT , of resistors R1, R2 and R3 connected in series is given by
RT = R1 + R2 + R3 This is an algebraic equation. If R1 = 6.3k, R2 = 2.4k and R3 = 8.5k, then
RT = 6.3+ 2.4+ 8.5 = 17.2k The temperature in Fahrenheit, F , is given by
F = 9 5 C + 32
C the This is an If C = 100◦C, then F = 9
5 × 100+ 32
= 180+ 32 = 212◦F. If you can cope with evaluating formulae then you will be able to cope with algebra.
