Tính:
\(B=-\frac{1}{3}+\frac{1}{3^2}-\frac{1}{3^3}+...+\)\(\frac{1}{3^{50}}-\frac{1}{3^{51}}\)
\(2\frac{3}{5}x-\frac{1}{7}=1\frac{9}{35}\)
\(\left(2\frac{4}{5}x+50\right):\frac{2}{3}=-51\)
Tìm x biết :
a)\(\frac{2}{3}x-50\%x-\left(-\frac{4}{5}\right):1\frac{3}{5}=-0,12\)\(+1\frac{3}{25}\)
b)\(\left(-1\frac{1}{6}+\frac{2}{3}-\frac{3}{4}\right):x+\left(-1\frac{11}{12}\right).1\frac{21}{23}=-6\frac{1}{3}\)
c)\(50\%x-\frac{1}{3}x-\left(\frac{-2}{3}\right)^2.\left(-1\frac{1}{8}\right)=-119\frac{3}{4}+120\frac{5}{6}\)
\(TÍNH\: GIA\: TRI\: BIEU\: THƯC\: A=\: \: \: \frac{1}{\frac{1}{\frac{100}{1}+}}+\frac{1}{\frac{2}{\frac{49}{2,}+}}+\frac{1}{\frac{3}{\frac{48}{3}+...+}}+...+\frac{1}{\frac{49}{\frac{2}{48}+\:\:}}+\frac{1}{\frac{50}{\frac{1}{50\:}}}\)\(\)
CTR:A=\(\frac{1}{26}+\frac{1}{27}+...+\frac{1}{49}+\frac{1}{50}=\frac{99}{50}-\frac{97}{49}+...+\frac{7}{4}-\frac{5}{3}+\frac{3}{2}-1\)
\(1+\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+...+50}\)
\(1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+...+\frac{1}{729}\)
Bài 1:tính nhanh
a. 6\(\frac{4}{5}\)-\(\left(1\frac{2}{3}+3\frac{4}{5}\right)\)
b. \(7\frac{5}{9}-\left(2\frac{3}{4}+3\frac{5}{9}\right)\)
c. \(\frac{-3}{5}.\frac{5}{7}+\frac{-3}{5}.\frac{3}{7}+\frac{-3}{5}.\frac{6}{7}\)
d. \(\frac{1}{3}.\frac{4}{5}+\frac{1}{3}.\frac{6}{5}-\frac{4}{3}\)
Bài 2: tìm x
a. \(\frac{2}{3}+\frac{1}{3}:x=\frac{3}{5}\)
b. \(x+30\%x=-1,3\)
c. \(3\frac{1}{3}x+16\frac{3}{4}=-13,25\)
d. \(\left(2\frac{4}{5}x-50\right):\frac{2}{3}=51\)
e. |2x-1|=\(\left(-4\right)^2\)
gấp nha các bạn !!!!!!!!
Bài 1: Thực hiện phép tính
a,\(22\frac{1}{2}.\frac{7}{9}+50\%-1,25\)
b,\(1,4.\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right):2\frac{1}{5}\)
c,\(\left(\frac{-1}{2}\right)^2-\frac{7}{16}:\frac{7}{4}+75\%\)
Bài 2: Tìm x
a,\(1\frac{3}{5}+\frac{7}{12}:x=\frac{-9}{4}\)
b,\(\left(2\frac{4}{5}.x+50\right):\frac{2}{3}=-51\)
c,\(|\frac{3}{4}.x-\frac{1}{2}|=\frac{1}{4}\)
