(a + b + c ) (a + b + c )
= a (squared) + ab + ac + ab + b (squared) + bc + ac + bc + c (squared)
= a (squared) + 2ab + 2ac + b (squared) + 2bc + c (squared)
Ayan na. XD naging "2ab" kasi ab + ab = 2ab. The same lang sa ac and bc. :) Tapos naging "a" (squared), because a x a = a (squared), the same lang din sa b and c. Get it? XD
