Skip to content / Đến nội dung
ThichHocToan.com

1954 AMC 12 Question 49

AMC12 · 1954 AMC 12

Question 49

The difference of the squares of two odd numbers is always divisible by $8.$ If $a>b,$ and $2a+1$ and $2b+1$ are the odd numbers, to prove the given statement we put the difference of the squares in the form:
  1. $(2a+1)^2-(2b+1)^2$
  2. $4a^2-4b^2+4a-4b$
  3. $4[a(a+1)-b(b+1)]$
  4. $4(a-b)(a+b+1)$
  5. $4(a^2+a-b^2-b)$