From 11:00PM PDT on Friday, July 1 until 5:00AM PDT on Saturday, July 2, the Shmoop engineering elves will be making tweaks and improvements to the site. That means Shmoop will be unavailable for use during that time. Thanks for your patience!

# At a Glance - Evaluating Algebraic Expressions

To evaluate an algebraic expression, just plug numbers into the expression and simplify it.

Don't Forget: you will need your faithful friend PEMDAS (aka Order of Operations).

Here's a video example of math in action. Practice, practice, practice.

#### Example 1

 Evaluate the expression when x = 2, y = -3, and z = -1.

#### Example 2

Find the values of the expression for x = -2, -1, 0, 1, 2

This question is asking us to evaluate the expression for five different values. It may be easiest to do this in chart form.

 X 3x2 + 1 Simplified -2 3(-2)2 + 1 3(-2)2 + 13(4) + 112 + 113 -1 3(-1)2 + 1 3(-1)2 + 13(1) + 13 + 14 3(0)2 + 1 3(0)2 + 13(0) + 10 + 11 1 3(1)2 + 1 3(1)2 + 13(1) + 13 + 14 2 3(2)2 + 1 3(2)2 +13(4) +112 + 113

#### Example 3

 Which of these values (-2, -1, 0, 1, 2) makes this equation true?Just like the previous problem, it is probably useful to make a chart.

#### Exercise 1

Evaluate the expression 3x2 + 5xy – 2 for x = 3 and y = -2.

#### Exercise 2

The formula for the surface area of a cone is πrs + πr2, where r is the radius of the base and s is the length of the slant. Find the surface area of a cone with radius 10 cm and a slant of 12 cm (use 3.14 for π).

#### Exercise 3

Evaluate the expression x3 + x2 + x + 1 for x values equal to -2, -1, 0, 1, 2.

#### Exercise 4

Which of these values of x (1, 2, 3, 4, 5, 6) make this equation true: x2 – 8x = -12?