Download Evaluating Expression

At the end of the period,
you should be able to:
1. Evaluate Expression
2. Apply the order of
operation in evaluating
algebraic expressions
Evaluating Expression
1
Evaluating Expressions
Evaluate the expression 2x – 3xy +4y when
x = 3 and y = -5.
To find the numerical value of the expression,
simply replace the variables in the expression with
the appropriate number.
Remember to use correct order of operations.
Example
Evaluate 2x–3xy +4y when x = 3 and y = -5.
Substitute in the numbers.
2(3) – 3(3)(-5) + 4(-5)
Use correct order of operations.
6 + 45 – 20
51 – 20
=31
Evaluating Example
Substitute in the numbers.
Remember correct order of operations.
For the expression 5x + 9y:
• Evaluate if x = 3 and y = -2.
For the expression 5x + 9y:
• Find x if y = 10 and the expression equals 120.
For the expression 5x + 9y:
• Find y if x = -7 and the expression equals 1