Question

7¹ + 7² +.....+ 7³⁶ chia 8 dư mấy

Answer 1

7+7²+7³+7⁴+...+7³⁶=(7+7²)+(7³+7⁴)+...+(7³⁵+7³⁶)

=7(1+7)+7³(1+7)+...+7³⁵(1+7)

=(7+7³+...+7³⁵).8 chia 8 dư 0

duyệt đi

Answer 2

7¹+7²+........+7³⁶

=18x7¹⁸

=4187349251769729

Answer 3

=(7^1+7^2)+............…+(7^35+7^36)

=7(1+7)+……………+7^35(1+7)

=7.8+…………………+7^35.8

suy ta: 7^1+7^2+………………+7^36 chia hết cho 8.

suy ra: 7^1+7^2+7^36 chia 8 dư 0

Answer 4

7¹ + 7² +.....+  7³⁶

=7¹⁸x18

->71 + 72 +.....+ 736 chia 8 dư 1

 

Answer 5

Đặt A = 7¹ + 7² + 7³ + .... + 7³⁶

=> A = ( 7¹ + 7² ) + ( 7³ + 7⁴ ) + ..... + ( 7³⁵ + 7³⁶ )

=> A = 7 ( 1 + 7 ) + 7² ( 1 + 7 ) + .... + 7³⁵ ( 1 + 7 )

=> A = 7.8 + 7².8 + .... + 7³⁵.8

=> A = 8.( 7 + 7² + .... + 7³⁵ )

Vì 8 : 8 dư 0 => A : 8 dư 0