Question

TĨM X BIẾT :

(X+2)+(X+4)+(X+6)+..........+(X+100)=2700

 

Answer 1

x + 2 + x + 4 + x + 6 + ..... + x + 100 = 2700

50x + 2 + 4 + 6 + ..... + 100 = 2700

50x + (100 + 2) x 50 : 2 = 2700

50x + 2550 = 2700

50x = 2700 - 2550 = 150

x = 150 : 50 = 3 

Answer 2

x + 2 + x + 4 + x + 6 + ... + x + 100 = 2700

50x + 2 + 4 + 6 + .... + 100 = 2700

50x + ( 100 + 2 ) x 50 : 2 = 2700

50x + 2550 = 2700

50x = 2700 - 2550 = 150

x = 150 : 50 = 3

Answer 3

=> ( x + x + x + .... x + x ) + ( 2 + 4 + 6 + .... + 100 ) = 2700

=> 50x + 2.( 1 + 2 + 3 + .... + 50 ) = 2700

=> 50x + 2.{ [ 50.( 50 + 1 ) ] : 2 } = 2700

=> 50x + 2.1275 = 2700

=> 50x + 2550 = 2700

=> 50x = 2700 - 2550

=> 50x = 150

=> x = 150 : 50

=> x = 3