Question

[Quách Quỳnh Bảo Ngọc]

Tìm x biết (x+1)/10+(x+1)/11+(x+11)/12=(x+1)/13+(x+1)/14

Answer 1

[Trần Đức Thắng]

\(\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}-\frac{x+1}{13}-\frac{x+1}{14}=0\)

\(\left(x+1\right)\left(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)

=> x + 1 = 0 ( vì 1/10 + 1/11 + 1/12 - 1/13 - 1/14  khac 0 )  

=> x = -1