- 1 decade agoFavorite Answer
It's a difference of two squares:
(A + B)(A - B) = A^2 - B^2
Therefore, (y-4/5)(y+4/5) = y^2 - 16/25
- aswkingfishLv 51 decade ago
Use the FOIL method to solve this First number times first number or Y times Y which is Y squared. Outer number times outer number. inner number times inner number. last number time last number. then combine like terms.