Question

tim x biet:x+2x+3x+...+10x=-165

Answer 1

x + 2x + 3x + ... + 10x = -165

x(1 + 2 + 3 + ... + 10) = -165

x . 55  = -165

x =  \(\frac{-165}{55}\)

x = -3

    Vậy x = -3

Answer 2

x+2x+3x+.....+10x=-165

x.(1+2+3+...+10)=-165

x.55=-165

x=-165:55

x=-11