Question

Chứng minh rằng:

1) ( 10^19+ 10^18+10^17) chia hết cho 555

2) ( 8^17-27^9- 9^13) chia hết cho 15

Answer 1

1) \(10^{19}+10^{18}+10^{17}=10^{16}.10^3+10^{16}.10^2+10^{16}.10=10^{16}.\left(1000+100+10\right)=10^{16}.1110\)

vì 1110 : 555 bằng 2 

=> ................... chia hết cho 555

Answer 2

1) ( 10¹⁹+ 10¹⁸+10¹⁷) chia hết cho 555

= 10¹⁷.10²+10¹⁸.10+10¹⁷

⁼ 10¹⁷.(10²+10+1)

= 10¹⁷.111

= 10¹⁶.10.111

= 10¹⁶.1110 = 10¹⁶.555.2

=> ( 10¹⁹+ 10¹⁸+10¹⁷) chia hết cho 555