Đáp án:
Giải thích các bước giải:
A=55.47+55.53-100.15=55.(47+53)-100.15=55.100-100.15=100.(55-15)=100.40=4000
B=$\frac{2^10.3^10-2^10.3^9}{3.6^9}$
B=$\frac{2^10.3^9.(3-1)}{3^10.2^9}$
B=$\frac{2.1.1}{3}$ =2/3
C=1-3+3^2-...+3^2018
3C=3-3^2+3^3-...+3^2019
3C-C=(3-3^2+3^3-...-3^2019)-(1-3+3^2-...+3^2108)=3^2019-1
C=(3^2019-1)/3