Combine like terms (x+6) (x+6)

X to the power of two and 6 to the power of two

So you have to use the FOIL method which stands for First, Outside, Inside, Last. Basically you take the first term from each of the parentheses, in this case they’re both x, and multiply them together, giving you x^2. Then outside, you take the two terms that are on the outside edges of the parentheses, so the one on the left from the left parenthesis and the one on the right from the right parenthesis. Multiply those and you get 6x. You do the opposite for inside so you take the one on the right from the left parenthesis and so on. Then last you take the last term from each of the parenthesis which is six. 6x6 is 36. You end up with X^2 + 6x + 6x + 36 which can be simplified to X^2 +12x + 36. Keep in mind you can only use FOIL if there are just two parentheses with just two terms inside each of them. Also it won’t always be written like the way you have it. Sometimes instead of (x+6)(x+6) they will write it as (x+6)^2. Hope this helps.