a) x^2-y^2 = (x - y)(x + y);
b)81-m^2 = (9 - m)(9 + m);
v)p^8-49 = (p^4 - 7)(p^4 + 7);
c)4a^2-9b^2 = (2a - 3b)(2a + 3b).
a) x^2-y^2 = (x - y)(x + y);
b)81-m^2 = (9 - m)(9 + m);
v)p^8-49 = (p^4 - 7)(p^4 + 7);
c)4a^2-9b^2 = (2a - 3b)(2a + 3b).