456
Giới thiệu về bản thân
\(1,\)
\(a,\dfrac{-9}{51}.\dfrac{17}{6}\)
\(=-1.\dfrac{1}{2}\)
\(=-\dfrac{1}{2}\)
\(b,\dfrac{-25}{32}.\left(-0,2\right)\)
\(=\dfrac{-25}{32}.-\dfrac{2}{10}\)
\(=\dfrac{-5}{16}.-\dfrac{1}{2}\)
\(=\dfrac{5}{32}\)
\(c,-15,2.3,5=-53,2\)
\(d,\dfrac{-8}{15}.1\dfrac{1}{4}\)
\(=\dfrac{-8}{15}.\dfrac{5}{4}\)
\(=\dfrac{-2}{3}.\dfrac{1}{1}\)
\(=\dfrac{-2}{3}\)
\(e,1\dfrac{2}{5}.\dfrac{-3}{14}\)
\(=\dfrac{7}{5}.\dfrac{-3}{14}\)
\(=\dfrac{1}{5}.\dfrac{-3}{2}\)
\(=-\dfrac{3}{10}\)
\(g,1\dfrac{1}{17}.1\dfrac{1}{36}\)
\(=\dfrac{18}{17}.\dfrac{37}{36}\)
\(=\dfrac{1}{17}.\dfrac{37}{2}\)
\(=\dfrac{37}{34}\)
\(#T.T\)
câu g là 1 và 1/7 ạ?
\(\left(3x+1\right):\left(-4\right)=-28\)
\(\left(3x+1\right)\) \(=-28.\left(-4\right)\)
\(3x+1\) \(=112\)
\(3x\) \(=112-1\)
\(3x\) \(=111\)
\(x\) \(=111:3\)
\(x\) \(=37\)
Vậy `x = 37`
\(#T.T\)
\(\left(x-\dfrac{1}{2}\right)\times\dfrac{5}{2}+\dfrac{1}{2}=\dfrac{7}{4}\)
\(\left(x-\dfrac{1}{2}\right)\times\dfrac{5}{2}\) \(=\dfrac{7}{4}-\dfrac{1}{2}\)
\(\left(x-\dfrac{1}{2}\right)\times\dfrac{5}{2}\) \(=\dfrac{5}{4}\)
\(x-\dfrac{1}{2}\) \(=\dfrac{5}{4}:\dfrac{5}{2}\)
\(x-\dfrac{1}{2}\) \(=\dfrac{1}{2}\)
\(x\) \(=\dfrac{1}{2}+\dfrac{1}{2}\)
\(x\) \(=1\)
\(#World\)
Bạn muốn hỏi gì?
\(3\times7\times20+12\times11\times5-2\times12\times30\)
\(=60\times7+60\times11-60\times12\)
\(=60\times\left(7+11-12\right)\)
\(=60\times6\)
\(=360\)
Vế phải đâu ạ?
Sửa đề
\(b,B=\dfrac{6}{2\times4}+\dfrac{6}{4\times6}+\dfrac{6}{6\times8}+...+\dfrac{6}{2020\times2022}\)
\(=3\times\left(\dfrac{1}{2\times4}+\dfrac{1}{4\times6}+\dfrac{1}{6\times8}+...+\dfrac{6}{2020\times2022}\right)\)
\(=3\times\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+...+\dfrac{1}{2020}-\dfrac{1}{2022}\right)\)
\(=3\times\left(\dfrac{1}{2}-\dfrac{1}{2022}\right)\)
\(=3\times\left(\dfrac{1011}{2022}-\dfrac{1}{2022}\right)\)
\(=3\times\dfrac{505}{1011}\)
\(=\dfrac{505}{337}\)
Thiếu c rồi.
\(\left(815+185\right)-\left(23+77\right)\)
\(=1000-100\)
\(=900\)