b) (3 * 2²⁰ + 7 * 2¹⁹) * 52/ (13 * 8⁴)² =
2¹⁹(3 * 2 + 7) * 13 * 2²/13² * 8⁸ =
2¹⁹ * 13 * 13 * 2²/13² * (2³)⁸ =
2²¹ * 13²/13² * 2²⁴ =
1/2³ =
1/8
c) 25 * (180 * 6⁷ - 108 * 6⁶)/216³ - 36⁴ =
25 * 6⁶(36 * 5 * 6 - 36 * 3 * 1)/(36³ * 6³ - 36⁴) =
25 * 6⁶ * 36(30 - 3)/36³(6³ - 36) =
25 * 36³ * 36 * 27/36³(36 * 6 - 36) =
25 * 36 * 27/36(6 - 1) =
25 * 27/5 =
5 * 27 =
5 * 3³ =
135
