At the end of this lesson, students should be able to:
Identify or recognise algebraic expressions.
Know the difference between an algebraic expression and an algebraic equation.
Know the meaning of coefficients and identify the coefficients of variables.
Add and subtract algebraic terms.
In algebra, we use letters and symbols to represent numbers. We can use algebra to obtain or display a general formula and hence use this formula to solve problems.
NOTE:
a + 5b – 7c is analgebraic expression.
a + 5b = 7c is an algebraic equation.
a = 7c – 5b is analgebraic formula.
It is important that you clearly understand the difference. An algebraic expression does not have an equality sign (=), but an algebraic equation and an algebraic formula has an equality sign. In an algebraic formula, the coefficient of the variable which is the subject of the formula must be 1. A formula is a general rule which enables the calculation of the value of one variable given the values of the other variables in the formula.
Coefficients
Example 1: What is the coefficient of p in 13p?
Solution: The coefficient ofp is 13.
Example 2: What is the coefficient of g in 13p – 4g?
Solution: The coefficient of g is -4.
Addition and subtraction of algebraic terms
You can only add or subtract terms that are the same. These are usually called like terms.