Answer:
You don't really need to do it, but it helps you keep things more organized and easier to follow. Imagine if you're doing some multi-variable equation,
2a + 5b + 4d + 3c + b + a + 2d
that looks like a mess, it'll be easier to look at if you put all the similar variables next to each others like this:
a + 2a + b + 5b + 3c + 2d + 4d
(a + 2a) + (b + 5b) + 3c + (2d + 4d)
now you can add them up much easier.
Answer:

Step-by-step explanation:

Answer:
Step-by-step explanation:
The difference of two squares may be represented by the formula: a^2-b^2,
which can be factored as (a+b)(a-b)
A perfect square trinomial may be represented by the formula: a^(2)-2ab+b^2 or a^(2)+2ab+b^2, depending on the sign of b
if b is negative: use the formula a^(2)-2ab+b^2, which can be factored as (a-b)*(a-b) or (a-b)^(2)
if b is positive: use the formula a^(2)+2ab+b^2, which can be factored as (a+b)*(a+b) or (a+b)^(2)
The answer to the question is 4