O L M

a. Có 5+4+3+2+1= 15 đoạn

\(5^{10}+5^{11}+5^{12}\)

\(=5\left(5^9+5^{10}+5^{11}\right)⋮5\)

⇒ \(5^{10}+5^{11}+5^{12}⋮5\)

5¹⁰ chia hết cho 5

5¹¹ chia hết cho 5

5¹² chia hết cho 5

=> 5¹⁰ + 5¹¹ + 5¹² chia hết cho 5

nhanh lên nha mik gấp lắm

\(\dfrac{8}{7}:\dfrac{24}{21}-x=\dfrac{15}{30}\)

\(1-x=\dfrac{1}{2}\)

\(x=1-\dfrac{1}{2}\)

\(x=\dfrac{1}{2}\)

\(\dfrac{8}{7}:\dfrac{24}{21-x}=\dfrac{15}{30}=\dfrac{1}{2}\)

\(\dfrac{24}{21-x}=\dfrac{8}{7}:\dfrac{1}{2}=\dfrac{16}{7}\)

\(336-16x=168\)

\(16x=168\)

\(x=\dfrac{21}{2}\)

1350 ; 1530 ; 1035; 3501; 3510;3051;3105;5013;5310;5130;5031

-                             1035,1053,1305,1350,1503,1530,3015,3051,3105,3150,3501,3510,5013,5031,5103,5130,5301,5310.

+) \(2004^{10}+2004^9\)

\(=2004^9\left(2004+1\right)=2004^9.2005\)

+) \(2005^{10}=2005^9.2005\)

Mà \(2005^9>2004^9\)

\(\Rightarrow2004^{10}+2004^9< 2005^{10}\)

0,2 . x - 75 : 2,5 = 6,08 : 0,04

<=> 0,2x - 30 = 152

<=> 0,2x = 182

<=> x = 910

0,2 x x - 75 : 2,5 = 6,08 : 0,04

0,2 x x - 50 = 152

0,2 x x = 152 + 50

0,2 x x = 202

x = 202 : 0,2

x = 1010

4/9 x X + 14/9 x X = 13,2 : 0,01

= 4/9 x X + 14/9 x X = 1320 

= X . ( 4/9 + 14/9) = 1320

= X . 2 = 1320

= X = 1320 : 2

= X = 660 

4/9 x X + 14/9 x X = 13,2 : 0,01

= 4/9 x X + 14/9 x X = 1320 

= X . ( 4/9 + 14/9) = 1320

= X . 2 = 1320

= X = 1320 : 2

= X = 660 

giải thích j bn