Question

[Dương Helena]

Tìm x biết:

\(\left(\frac{2}{11.13}+\frac{2}{13.15}+...+\frac{2}{19.21}\right).462-\left[2,04:\left(x+1,05\right)\right]:0,12=19\)

Answer 1

[Devil]

\(\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-...+\frac{1}{19}-\frac{1}{21}\right).462-\left[2,04:\left(x+1,05\right)\right]:0,12=19\)

\(\left(\frac{1}{11}-\frac{1}{21}\right).462-\left[2,04:\left(x+1,05\right)\right]:0,12=19\)

\(\frac{10}{231}.462-\left[2,04:\left(x+1,05\right)\right]:0,12=19\)

\(20-\left[2,04:\left(x+1,05\right)\right]:0,12=19\)

\(\left[2,04:\left(x+1,05\right)\right]:0,12=20-19=1\)

\(2,04:\left(x+1,05\right)=0,12\)

\(x+1,05=2,04:0,12\)

x+1,05=17

x=17-1,05=15,95

Answer 2

[Ngân Tống]

cảm ơn bn nha