Question

tìm x thuộc n , biết

(x+1) + ( x + 2 ) + ( x + 3 ) + ... + ( x+ 100 ) = 5750

Answer 1

( x + 1 ) + ( x + 2 ) + ( x + 3 ) + ............  + ( x + 100 ) = 5750

( x + x + x + .......... + x ) + ( 1 + 2 + 3 + ........ + 100 ) = 5750

=> 100x + 5050 = 5750

100x = 5750 - 5050

100x = 700

     x = 700 : 100

     x = 7

Answer 2

100x +(1+2+3+...+100)=5750

100x + (100+1)x100 :2 = 5750

100x + 10100:2=5750

100x+ 5050 =5750

100x=5750=5050=700

x=700 :100 = 7

Answer 3

( x + 1) + (x + 2) + ( x+ 3) + ...+ ( x + 100) = 5750

x . (1 + 2 + 3 +... + 100) = 5750

x. [ (100-1) :1 + 1= 100 (số hạng) ] = 5750

x. [ (1 + 100) . 100 : 2 = 5050 ] = 5750

x . 5050 = 5750

x = 5750 : 5050 

x = \(\frac{115}{101}\)

Answer 4

 Số x là : 

( 100 - 1 ) : 1 + 1 = 100 

100x + ( 1 + 2 + 3 + ... + 100 ) = 5750

1 + 2 + 3 + .. + 100 = ( 100 + 1 ) . 100 : 2 = 5050

100x + 5050 = 5750

=> 100x = 5750 - 5050 = 700

     x = 700 : 100  = 7

Answer 5

     ( x + 1 ) + ( x + 2 ) + ( x + 3 ) + .... + ( x + 100 ) = 5750

=> x + 1 + x + 2 + x + 3 + .... + x + 100 = 5750

=> ( x + x + x + .... + x ) + ( 1 + 2 + 3 + .... + 100 ) = 5750

=> 100x + 100 x 101 : 2 = 5750

=> 100x + 5050 = 5750

=> x = ( 5750 - 5050 ) : 100

=> x = 7