\(-\left(+51\right);-|-39|;-37;0;|-18|;-\left(-19\right);25\)

\(A=3+3^2+3^3+3^4+...+3^{10}\)

=> \(A=\left(3+3^2\right)+\left(3^3+3^4\right)+...+\left(3^9+3^{10}\right)\)

=> \(A=3\left(1+3\right)+3^3\left(1+3\right)+...+3^9\left(1+3\right)\)

=> \(A=3.4+3^3.4+...+3^9.4\)

=> \(A=4\left(3+3^3+...+3^9\right)\)chia hết cho 4 (Đpcm)

A = 3 + 3² + 3³ + ... + 3⁹ + 3¹⁰

=> A = ( 3 + 3² ) + ( 3³ + 3⁴ ) + ... + ( 3⁹ + 3¹⁰ )

=> A = 3( 1 + 3 ) + 3³( 1 + 3 ) + ... + 3⁹( 1 + 3 )

=> A = 3 . 4 + 3³ . 4 + ... + 3⁹ . 4

=> A = ( 3 + 3³ + ... + 3⁹ ) . 4 chia hết cho 4

=> A chia hết cho 4

Vậy...

a, (18+29) +(158-18-29)

= 18+29+158-18-29

= (18-18) +(29-29)+ 158

= 158

b, (13-135+49)- (13+49)

= 13-135+49-13-49

= (13-13) +(49-49) -135

= 135

a, \(\left(18+29\right)+\left(158-18-29\right)\)

\(=18+29+158-18-29\)

\(=\left(18-18\right)+\left(29-29\right)+158\)

\(=158\)

b,

\(\left(13-135+49\right)-\left(13+49\right)\)

\(=13-135+49-13-49\)

= \(\left(13-13\right)+\left(49-49\right)-135\)

= \(-135\)

Ta có : 

112=7.2.2.2.2

140=2.2.5.7

Có x là số mà 112 và 140 cũng chia hết

Mà :10 < x < 20

=> : 2.7=14

Vậy x=14

đung roi

18+29+158-18-29

=(18-18)+(29-29)+

=158

(18+29)+(158-18-19)

=47+121

=168

(13-135+49)-(13+49)

= -73-62

=-135

Happy birthday cj gái chức cj sn vui vẻ nhé. You have got a mail là cj cs tin nhắn nhé

(18+29) +( 158 -18-29)

= 18 + 29 + 158 - 18 - 29

= 18 - 18 + 29 - 29 + 158

= 0 + 0 + 158

= 158

(13-135+49)-(13+49)

= 13 - 135 + 49 - 13 - 49 

= 13 - 13 + 49 - 49 - 135

= 0 + 0 -135

= -135

( 18 + 29 ) + ( 158 - 18 - 29 )

= 18 + 29 + 158 - 18 - 29

= ( 18 - 18 ) + ( 29 - 29 ) + 158

= 0 + 0 + 158

= 158

( 13 - 135 + 49 ) - ( 13 + 49 )

= 13 - 135 + 49 - 13 - 49

= ( 13 - 13 ) + ( 49 - 49 ) - 135

= 0 + 0  - 135

= -135