Tìm x: 1/21+1/28+1/36+...+2/x.(x+1)=2/9
tìm x: 1/21+1/28+1/36+...+1/x.(x+1)=2/9
1/21+1/28+1/36+............+2/x*(x+1)=2/9
Tìm x
tìm x biết
1/21+1/28+1/36+....+2/x.[x+1]+=2/9
Tìm x biết :
1/21 + 1/28 + 1/36 + ... + 2/x(x+1) = 2/9
tìm x
1/21 + 1/28 + 1/36 + ... + 2/x. ( x + 1 ) = 2/9
Tìm x thuộc N
1 / 21 + 1 / 28 + 1 / 36 + ... + 2 / x . ( x + 1 ) = 2 / 9
Tìm x biết:
1/21+1/28+1/36+...2(x+1)=2/9
tìm x thuộc N biết:
\(\dfrac{1}{21}+\dfrac{1}{28}+\dfrac{1}{36}+....+\dfrac{2}{x\left(x+1\right)}=\dfrac{2}{9}\)
