Question

Tìm x :

\(\left(\frac{2}{11\times13}+\frac{2}{13\times15}+...+\frac{2}{19\times21}\right)\times462-2,04\div\left(x+15\right)+11,02=30\)

Answer 1

\(\left(\frac{2}{11\times13}+\frac{2}{13\times15}+...+\frac{2}{19\times21}\right)\times462-2,04\div\left(x+15\right)+11,02=30\)

\(\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+...+\frac{1}{19}-\frac{1}{21}\right)\times462-2,04\div\left(x+15\right)+11,02=30\)

\(\left(\frac{1}{11}-\frac{1}{21}\right)\times462-2,04\div\left(x+15\right)=30-11,02\)

\(\frac{10}{231}\times462-2,04\div\left(x+15\right)=18,98\)

\(20-2,04\div\left(x+15\right)=18,98\)

\(2,04\div\left(x+15\right)=20-18,98\)

\(2,04\div\left(x+15\right)=1,02\)

\(x+15=2,04\div1,02\)

\(x+15=2\)

\(x=2-15\)

\(x=-13\)