Răspuns :
x +2x+3x+.....+10x =56x-3
x. 10(1+10)/2 = 11.5.x = 55x;
56x - 3 = 55x;
x = 3.
x. 10(1+10)/2 = 11.5.x = 55x;
56x - 3 = 55x;
x = 3.
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
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x(1+2+3+...+10) = 56x - 3
x* (10*11)/2 = 56x - 3
55x = 56x - 3
- x = - 3
x = 3 ∈ Q
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