refresher

When a question asks you to "evaluate" a situation, you are most likely being asked to find a numerical answer. The process is simple. Replace the variable in the expression or equation, with the numerical value you are given, and simplify the result.

hint gal
When evaluating an expression:
Remember to follow the proper order of operations and to watch out for those pesky negative signs. Placing a set of parentheses around the value being substituted will help you avoid errors with signs.

expin1
Evaluate x2 - 1, when x = 5.
   
Replace x with 5 and simplify.
   
(5)2 - 1 = 25 - 1 = 24 Answer
     
expin2
Evaluate a2b + a, when a = -3 and b = 2.
bewareS
Do NOT write:
-32(2) + (-3) as this is
-9(2) + (-3) = -21
   
Parentheses are needed in this problem.
   
(-3)2(2) + (-3) = 18 + (-3) = 15 Answer


   
expin3
Evaluate x3 + 3x2 - 2x - 5, when x = -4.
   
Again, use parentheses to avoid errors.
   
(-4)3 + 3(-4)2 - 2(-4) - 5 = -64 + 48 + 8 - 5 = -13 Answer
     
   
It may be the case that you will be asked to evaluate an expression using another expression.
Don't panic!!! Just follow the same process as you did when evaluating for a number.

expin4
Evaluate x2 + 2x - 4, when x = 2a.
   
Remember to use parentheses!
   
(2a)2 + 2(2a) - 4 = 4a2 + 4a - 4 Answer


   
expin5
Evaluate 3x + 10 when x = 3m + 15
   
Remember to use parentheses!
   
3(3m + 15) + 10 = 9m + 45 + 10 = 9m + 55 Answer



dash

The graphing calculator can also be used to evaluate expressions.
Click on the link at the right to see the possibilities.
ti84c
For calculator help with Evaluating Expressions
click here.

divider

NOTE: The re-posting of materials (in part or whole) from this site to the Internet is copyright violation
 and is not considered "fair use" for educators. Please read the "Terms of Use".