Question

Chứng minh : A = 3¹ + 3² + ... + 3¹⁰⁰ chia hết cho 12

Answer 1

12+3²(3+3²)+...+3⁹⁸(3+3²)

=1.12+3²(3+3²)+...+3⁹⁸(3+3²)

=(1+3²+...+3⁹⁸)12