Respuesta :

sqdancefan

Answer:

  • t^2 - 1
  • n^2 - 225

Step-by-step explanation:

For an expression to be a difference of squares, it must be a difference of two terms, each of which is a square. A term is a square if its coefficient is a square and if its degree is even.

The third expression is a sum, not a difference; the fourth expression has a term that is not a square (40). Neither of those is a difference of squares.