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daca x+2x+3x+...+99x=9900 atunci x=?​

Răspuns :

x + 2x + 3x + ... + 99x = 9900

x·(1 + 2 + .. + 99) = 9900

x·(99x100 : 2) = 9900

x·4950 = 9900

x = 9900 : 4950

x = 2

x(1+2+3+...+99)=9900

x[(1+99)×99]:2=9900

x × 4950 = 9900

x=9900÷4950=2