Question

Tìm a 

a + 2 x a + 3 x a + ...... + 99 x a +100 x a = 25250

Answer 1

<=> a + 2a + 3a + .... + 99a + 100a = 25250 

<=> a.(1+ 2 + 3 + .... + 99 + 100) = 25250 

<=> a. 5050 = 25250 

<=> a = 25250 : 5050 

<=> a = 5

Answer 2

a + 2 x a + 3 x a + ...... + 99 x a + 100 x a = 25250

( 1 + 2 + 3 + ... + 99 + 100 ) x a = 25250

5050 x a = 25250

a = 25250 : 5050

a = 5

Answer 3

a + 2 x a + 3 x a + ..... + 99 x a + 100 x a = 25250 

= 1 x a + 2 x a + 3 x a + .... 99 x a + 100 x a = 25250

= a x ( 1 + 2 + 3 + ... + 99 + 100 ) = 25250

= a x 5050 = 25250

= a = 25250 : 5050 = 5 

Vậy a = 5.

Answer 4

1x2x3x...x100 + 100a =25250

=..... 

= tích đó dài quá ko tính được

Answer 5

a( 1+2+3+..+100)=25250

a. ((1+100).100)/2=25250

a.5050              =25250

a                     = 25250/5050=5

Answer 6

a+2a+3a+.......+99a+100a =25250

a(1+2+3+4+.......+99+100)=25250

a x 5050 =25250\

a=25250:5050

a=5

(chú ý 2a =2 x a......)

Answer 7

Ta có:

1a + 2a + 3a +....+ 100a = 25250

=>a x ( 1 + 2 + 3 +...+ 100 ) = 25250

=> a x 5050 = 25250

=> a = 25250 : 5050 = 5

Answer 8

bang 5

Answer 9

<=> a + 2a + 3a + .... + 99a + 100a = 25250 

<=> a.(1+ 2 + 3 + .... + 99 + 100) = 25250 

<=> a. 5050 = 25250 

<=> a = 25250 : 5050 

<=> a = 5

Answer 10

   a + 2a + 3a + ... + 99 x a + 100 x a  = 25250

= a x ( 1 + 2 + 3 + ... + 99 + 100 ) = 25250

= a x 50 = 25250

=> a = 25250 : 50

=> a = 5

Answer 11

Vu Dinh Dung

a + 2a + 3a + ... + 99 x a + 100 x a = 25250

= a x ( 1 + 2 + 3 + ... + 99 + 100 ) = 25250

= a x 50 = 25250

=> a = 25250 : 50

=> a = 5 

Answer 12

Theo đề: a + 2 x a + 3 x a + ...... + 99 x a +100 x a = 25250

\(\Leftrightarrow\) a + 2a + 3a + .... + 99a + 100a = 25250 

 \(\Leftrightarrow\) a.(1+ 2 + 3 + .... + 99 + 100) = 25250 

\(\Leftrightarrow\) a. 5050 = 25250 

\(\Leftrightarrow\) a = 25250 : 5050 

\(\Leftrightarrow\) a = 5

VẬY