Joe is building a post for his mailbox. to find the correct dimensions, he needs to expand this expression: (x-3) (x-9) (x-4) select the equivalent expression written in the format ax3(cubed) + bx2(squared) +cx+d

Step-by-step explanation:

Given:

The expression to expand is given as:

Let us expand the first two binomials of the given expression using FOIL method.

The FOIL method states that:

Now, let us multiply the result with the remaining binomial. Multiplying each term of the trinomial with each term of the binomial, we get:

Therefore, the equivalent expression after expanding is given as:

1. perpendicular

2. parallel

3. perpendicular