Question

calculati 5+10+15+.....+2020-5× (1+2+3+....+404)

Answer 1

Răspuns:

Explicație pas cu pas:

5 + 10 + 15 + ..... + 2020 - 5 × ( 1 + 2 + 3 + ....+ 404 ) = 0

= 5 × ( 1 + 2 + 3 + .....+ 404 )  - 5 × ( 1 + 2 + 3 + ... + 404 ) =

= 0

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Iata si calculele

5 × ( 1 + 2 + 3 + .....+ 404 )  - 5 × ( 1 + 2 + 3 + ... + 404 ) = 0

= 5 × 404 × ( 1 + 404 ) : 2  - 5 × 404 × ( 1 + 404 ) : 2 =

= 5 × 202 × 405 - 5 × 202 × 405 =

= 1010 × 405 × ( 1 - 1 ) =

= 1 010 × 405 × 0 =

= 0