Question

dati factor comun si calculati urmatoarele sume;
S=5,10,15...300
S=7,14,21,28,35...700
S=11,22,33,...264

Answer 1

Răspuns

Explicație pas cu pas:

S = 5 + 10 + 15 + ...... + 300

S = 5 × ( 1 + 2 + 3 + ....... + 60 )

S = 5 × 60 × ( 1 + 60 ) : 2

S = 300 × 61 : 2

S = 9 150

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S = 7 + 14 + 21 + 28 + ...... + 700

S = 7 × ( 1 + 2 + 3 + 4 + ...... + 100 )

S = 7 × 100 × 101 : 2

S = 35 350

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S = 11 + 22 + 33 + ....... + 264

S = 11 × ( 1 + 2 + 3 + .......+ 24 )

S = 11 × 24 × ( 1 + 24 ) : 2

S = 11 × 12 × 25

S = 3 300