Algebraic Techniques
- A pronumeral is a letter or symbol used to represent a number in algebra. For example, in x+5 the letter x is a pronumeral.
- When a pronumeral can take different values, it’s called a variable.
- If the value is fixed, it’s called a constant. Example : 5
- An algebraic expression is made up of numbers, pronumerals, and operations like addition, subtraction, multiplication, and division. Examples: 3x, 2a+5, x/2+4
- An expression does not have an equals sign — it’s different from an equation.
Algebra uses a neat way to write operations:
- ab means a × b
- xyz means x × y × z
- a2 means a × a
- y3 means y × y × y
- a/b means a÷b
- Write 4x, and not 4 × x
Focus on English
Write algebraic expressions from everyday language and vice versa.
Examples:
- “Five more than a number” → x+5
- “A number divided by 3” → x/3
- “Double a number and subtract 7” → 2x−7
Substitution means replacing the pronumeral with a number:
Example:
If x=3 then: 4x+1 = 4(3)+1 = 12 +1= 13
Algebra can describe patterns in numbers
Example: Pattern: 3, 5, 7, 9, 11; Expression: 2n+1 (where n is the position in the pattern)
Like and Unlike Terms
Like terms have the same variable and power.
You can add or subtract them.
Examples: 3x+4x = 7x; 5a−2a = 3a
If terms are not like terms, you cannot combine them.
For example: 2x+3y; 4a + 2b; stays the same.
Properties of Arithmetic in Algebra
- Commutative Property: Order doesn’t matter for addition or multiplication
a+b = b+a & ab = ba - Associative Property: Grouping doesn’t change the result: (a+b)+c = a+(b+c)
- Distributive Property: You multiply the number outside the brackets by each term inside: a(b+c) = ab+ac
- Factorizing: You factor out the common factor and put it back into brackets:
ab+ac = a(b+c)
Solve the following Questions on Basic Algebraic Operations:
- Write the following using algebraic notation: “Multiply 6 by a number y, then divide the result by 3.”
- The cost of x movie tickets is given by the expression 15x. If you buy 4 tickets, what is the total cost?
- Use the algebraic expression 2n+1 to generate the first 4 numbers in the pattern when n=1,2,3,4.
- Simplify the expression: 3x+5−2x+7
- Expand and simplify: 3(x+4)
- Factorize: 12x+12y
🔄 Answers:
- 6y/3 = 2y
- The total cost is 15×4 = 60
- 3, 5, 7, and 9
- 3x+5−2x+7 = x+12
- 3(x+4) = 3x+12
- 12x+12y = 12(x+y)