Question

1.2.3+2.3.4+...+48.49.50

 

Answer 1

ủng hộ mình nha

Answer 2

Đặt A = 1.2.3 + 2.3.4 + .... + 48.49.50

=> 4A = 1.2.3.4 + 2.3.4.4 + .... + 48.49.50.4

=> 4A = 1.2.3.( 4 - 0 ) + 2.3.4.( 5 - 1 ) + .... + 48.49.50.( 51 - 47 )

=> 4A = 1.2.3.4 + 2.3.4.5 - 1.2.3.4 + ..... + 48.49.50.51 - 47.48.49.50

=> 4A = ( 1.2.3.4 - 1.2.3.4 ) + ( 2.3.4.5 - 2.3.4.5 ) + .... + ( 47.48.49.50 - 47.48.49.50 ) + 48.49.50.51

=> 4A = 48.49.50.51

=> A = ( 48.49.50.51 ) : 4

=> A = 1499400

Answer 3

Gọi biểu thức đó là A

4A=1.2.3.4+2.3.4.4+...+48.49.50.4

4A=1.2.3.(4-0)+2.3.4.(5-1)+...+48.49.50.(51-47)

4A=1.2.3.4-0.1.2.3.4+2.3.4.5-1.2.3.4+....+48.49.50.51-48.49.50

4A=48.49.50.51-0.1.2.3

A=48.49.50.51/4=1499400

Ủng hộ mk nha

 

Answer 4

1499400 nhé bạn

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