👤

rezolvati ecuatiile x+(x+1)+(x+2)+...+(x+11)=78



Răspuns :

x+(x+1)+(x+2)+...+(x+11)=78
12x+(1+2+...+11)=78
12x+11x12:2=78
12x+11x6=78
12x+66=78
12x=12
x=1