Download Evaluating Expressions

Evaluating Expressions
1
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
2
2
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.
Evaluating Expressions
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
2
x
2
3y
Evaluate – 4xy +
when x = 2 and y = -1
Substitute: (2)2 – 4(2)(-1) + 3(-1)2
Use the correct order of Operations
= 4 – 4(2)(-1) + 3(1)
=4+8+3
= 15
Practice Exercises
• For the expression 5x + 9y:
Evaluate if x = 3 and y = -2
5x + 9y = 5(3) + 9(-2)
= 15 + (-18)
= -3
Practice Exercises
• For the expression 5x + 9y:
Find x if y = 10 and the expression equals 120
5x + 9(10) = 120
5x = 30
x=6
Practice Exercises
• For the expression 5x + 9y:
Find y if x = -7 and the expression equals 1
5(-7) + 9y = 1
9y = 36
y=4