Introduction to Graphs:

Describe the Concept of a Function (or Formula)

The first video in this lesson will go over the following vocabulary words:

Expression = A statement using numbers and/or variables and an operator
Equation = Expressions with an equal sign (=)
Formula = An equation that gives us instructions or a rule
Function = An equation where every input has only one output

The following video will explain more about how a function works using the metaphor or parable of a seed. Just as a seed is only able to produce the one plant it is meant to create, a function can only produce one output for each input value.

Video Source (02:22 mins) | Transcript

This video references the following talk by Elder Uchtdorf: God's Harvest

Practice Problems

Choose the answer that will correctly complete the following sentence. Each unique input into a function can lead to ____.
1. only one output
2. several outputs
3. a random number of outputs
Choose the answer below that is an expression.
1. 3x = 2
2. 5 + 1 = x
3. 3 − 1
Choose the answer below that is an equation.
1. 3 + 4
2. 2x
3. 5 + 1 = x − 2

Solutions

a. only one output
c. 3 − 1 (Written Solution)

There is only one expression listed. It is 3 − 1. Equations have equal signs in them. Expressions do not. Expressions have numbers, variables, and operations but not an equal sign. (Some examples of operations are addition, subtraction, multiplication, etc.)
c. 5 + 1 = x − 2 (Written Solution)

There is only one equation listed. It is: 5 + 1 = x − 2. We know it is an equation because it contains an equal sign.