can someone help please ?

Answer:
yes they are
Step-by-step explanation:
(a-b)² = (a-b)×(a-b) = a²-b²
Answer:
No they are not
Step-by-step explanation:
squaring that expression will come out to be a^2-2ab+b^2
this is because you are doing (a-b)(a-b), so you have to multiply each term from the first set of parenthesis by each term in the second set of parenthesis.
a^2-ab-ab+b^2
a^2-2ab+b^2
(a-b)^2≠a^2-b^2