Question

( 3y + 1 )( 3y - 1 )Determine each product

Answer 1

It is important to know that a Product is the result of a multiplication.

You have the following expression given in the exercise:

`\mleft(3y+1\mright)\mleft(3y-1\mright)​`

Notice that it is the multiplication of two Binomials and it has this form:

`(a+b)(a-b)`

By definition:

`(a+b)(a-b)=a^2-b^2`

This is called "Difference of two squares".

You can identify that, in this case:

`\begin{gathered} a=3y \\ b=1 \end{gathered}`

Therefore, you get:

`\mleft(3y+1\mright)\mleft(3y-1\mright)​=(3y)^2-(1)^2=9y^2-1`

The answer is:

`9y^2-1`