Question

X+8/5.9+8/9.13+8/13.17+....+8/41.45= -74/45

Answer 1

\(\Leftrightarrow x+2\left(\dfrac{4}{5\cdot9}+\dfrac{4}{9\cdot13}+...+\dfrac{4}{41\cdot45}\right)=\dfrac{-74}{45}\)

\(\Leftrightarrow x+2\cdot\left(\dfrac{1}{5}-\dfrac{1}{45}\right)=-\dfrac{74}{45}\)

hay x=-2

Answer 2

x = -2 nha bạn

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