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2.1 A) Algebra Key Terms

Algebra – Key Terms
In this section, we are going to look at a few different key terms that relate to algebra.
 
Algebraic expressions contain letters that stand for variable values or unknown values:

• Variable values are values that can change. An example of when a letter is a variable value is a graph, such as the graph y = 2x.
• Unknown values for terms are found by solving the equation that we are either given or equations that are created from information that we are given. An example would be: x + 5 = 7.

 
Terms & Expression
 A term is a number or letter that is on its own. An expression is a set of terms that are combined.
 
For example, here is an expression:

This is an expression because there are many terms that are joined together. In the expression above, there are 3 different terms, which are 10x², -7x and 24.

Equations
An equation is where there are two expressions that are equal to one another. With the example for the unknown value that we used earlier (x + 5 = 7), the expressions “x + 5” and “7” are equal to one another.

Identity
An identity is a statement that is true no matter what values are chosen for the unknowns. The symbol for an identity is ≡. An example of an identity is:

The left and right side of the identity will be the same for any value of y. Let’s show that this is the case by subbing in y as 2. When we sub in y as 2, we need to remember BIDMAS; Brackets, Indices, Division, Multiplication, Addition and Subtraction (or BODMAS; the O in BODMAS stands for other). 

Let’s check anther value for y. I am now going to let y be 3.

This identity will hold for any value of y and we will be looking at how we can prove this in a later section.