Identify variables, constants, and coefficients in algebraic expressions and word problems. Fill in a table for expressions.

Here are the answers to the exercise:

1. Are the following examples of variables or constants?

• a) The number of hours in a day: Constant
• b) The number of hours of daylight in a day: Variable
• c) The number of sides in a pentagon: Constant
• d) The perimeter of pentagons: Variable

2. What information do you need to answer the following questions?

• a) How much does it cost to make a telephone call?
  • You need the cost per minute/call and the duration of the call.
• b) What is the area of a rectangle?
  • You need the length and width of the rectangle.
• c) How tall is a tree?
  • You need the height measurement of the tree.
• d) How much would you pay to make 5 phone calls?
  • You need the cost per phone call.

3. Copy the following table into your answer book and fill in the variable(s), constant(s) and the coefficient(s) of each algebraic expression:

• a) Expression: 3

  • Variable(s): None
  • Constant(s): 3
  • Coefficient(s): None

• b) Expression: $5x$

  • Variable(s): $x$
  • Constant(s): None
  • Coefficient(s): 5 (for $x$)

• c) Expression: $x-1$

  • Variable(s): $x$
  • Constant(s): $-1$
  • Coefficient(s): 1 (for $x$)

• d) Expression: $\frac{x}{2} - 3 \times n + 7 \div y - 4$

  • Variable(s): $x, n, y$
  • Constant(s): $-4$
  • Coefficient(s): $\frac{1}{2}$ (for $x$), $-3$ (for $n$), 7 (for $y^{-1}$ in $\frac{7}{y}$)