Question

[Nguyễn Hữu Triết]

Tìm x biết:

 x + \(\frac{4}{5.9}+\frac{4}{9.13}+...+\frac{4}{41.45}=\frac{-37}{45}\)

Answer 1

[Cậu Nhok Lạnh Lùng]

x + 4/5.9 + 4/9.13 + ... + 4/41.45 = -37/45

<=> x + 1/5 - 1/9 + 1/9 - 1/13 + ... + 1/41 - 1/45= -37/45

<=> x + 1/5 - 1/45 = -37/45

<=> x + 9/45 = -36/45

<=>x= -45/45=-1

Answer 2

[DanAlex]

CÓ: x+1/5-1/9+1/9-1/13+....+1/41-1/45=-37/45

=> x+(1/5-1/45)=-37/45

=> x+8/45=-37/45

=> x=-37/45-8/45

=> x=-45/45=-1

vậy x=-1