## Tuesday, 18 February 2014

### Algebra: Equation vs Expression

(I) Algebraic Expressions vs Equations
The following are expressions
• 3x
• 5 - 2y
• p + 2q - 45
• mn
The following are equations:
• 2x = 4
• x + 8 = 20
• x² = 36
• 2x + y = 4
Can you tell the difference between an expression and an equation?

(II) Coefficients, Variables and Constants
In the following algebraic expressions:

(a) 6x
• x is a variable
• 6 is the coefficient of x
• There is no constant
(b) 2y + 5
• y is a variable
• 2 is the coefficient of y
• 5 is the constant
(c) 3m + 7n + 9
• m and n are variables
• 3 and 7 are coefficients of m and n respectively
• 9 is the constant
(d) p + 2q - 45
• p and q are variables
• 1 and 2 are coefficients of p and q respectively
• -45 is the constant
(e) 5a - 3b + 1
• a and b are variables
• 5 and -3 are coefficients of a and b respectively
• 1 is the constant
(f) x - y
• x and y are variables
• 1 and -1 are coefficients of x and y respectively
• There is no constant
When given an expression, are you able to pick out the variable(s), coefficient(s) and constant terms?