Question

rezolvati ecuatia :x +2x+3x+.....+10x =56x-3, x apartine Q

Answer 1

x +2x+3x+.....+10x =56x-3
x. 10(1+10)/2 = 11.5.x = 55x;
56x - 3 = 55x;
x = 3.

Answer 2

x +2x+3x+.....+10x = 56x - 3
   x(1+2+3+...+10)   = 56x - 3
         x* (10*11)/2    = 56x - 3
                    55x  =  56x - 3
                       - x = - 3
                         x = 3 ∈ Q
                        =====