Iwas wondering if anyone could explain how to solve this?
explain the difference in the final product of these two
polynomial expressions: (a + b)^2 and (a – b)^2 why does that difference occur?

(a+b)² can also be written as (a+b) (a+b). When you expand this you get a²+2ab+b²

(a-b)² can also be written as (a-b) (a-b). When expanded this gives a²-2ab-b2

As you can see, this leads to different coefficients of the 'ab' values: for (a+B) ² its 2 for (a-b) ² its - 2

The answer would be 2 times 3 plus 8 divided by 8 = 7