my post is still on this page as algebra, could someone elaborate on what bobpursley tried to help me with.

See your original post.

I am guessing you are referring to your question

5)Simplify:(5x-4)^2

and your answer= 25x^2 - 16

(5x-4)^2
=(5x-4)(5x-4)
= 25x^2 - 20x - 20x + 16
= 25x^2 - 40x + 16

The FOIL that bobpurseley was referring to means
F - multiply the firsts
O - multiply the outside terms
I - multiply the inside terms
L - multiply multiply the last terms

it is a short memory-aid to help you multiply two binomials

Multiply 3/7 times 9/10

It looks like you are asking for an explanation of the solution provided by bobpursley in response to your question about simplifying the expression (5x-4)^2.

To simplify this expression, you can use the concept of expanding a binomial squared. The expression (5x-4)^2 means that you need to multiply (5x-4) by itself.

bobpursley started by applying the FOIL method, which stands for "First, Outer, Inner, Last." The FOIL method is a mnemonic device to remember the steps involved in multiplying two binomials.

First, you multiply the first terms of both binomials, which in this case are 5x and 5x. This gives you 25x^2.

Next, you multiply the outer terms, which in this case are 5x and -4. This gives you -20x.

Then, you multiply the inner terms, which are -4 and 5x. This also gives you -20x.

Lastly, you multiply the last terms of both binomials, which are -4 and -4. This gives you +16.

After performing these calculations, bobpursley combined the results to obtain the simplified expression: 25x^2 - 20x - 20x + 16. By combining like terms, the final solution becomes 25x^2 - 40x + 16.

So, in summary, bobpursley used the FOIL method to expand the expression (5x-4)^2 and performed the necessary calculations to simplify it.