# 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?