Chó biểu thức :

 \(\text{A}=\frac{\left(2-1\frac{2}{5}\right)^2+\left|1-\frac{12}{5}\right|-\left(-\frac{2}{5}\right)^2}{\frac{1}{2}-\frac{3}{7}:\left(-2\frac{1}{7}\right)+\left|\frac{1}{5}-\frac{1}{2}\right|-\frac{2}{5}}\).

\(\text{B}=\frac{6:\frac{3}{5}+1\frac{1}{6}\cdot\frac{6}{7}+\left(\frac{1}{3}-\frac{1}{4}-\frac{1}{12}\right)}{\frac{4}{11}-\frac{2}{22}+5\frac{2}{11}-\left(\frac{6}{-11}\right)}\).

Tính : \(\frac{\text{A}}{\text{B}}\).

(Trích đề thi HKI 7_Cô giáo dạy toán Phạm Thị Hồng Duyên-THCS Nghiêm Xuyên--Huyện Thường Tín--Tp. Hà Nội)

( Câu siêu khó dành cho học sinh đội tuyển Toán )

( Giúp với )

Bài 10 :

b) \(\frac{\left(\text{13}\frac{\text{1}}{\text{4}}-\text{2}\frac{\text{5}}{\text{27}}-\text{10}\frac{\text{5}}{\text{6}}\right).\text{230}\frac{\text{1}}{\text{25}}+\text{46}\frac{\text{3}}{\text{4}}}{\left(\text{1}\frac{\text{3}}{\text{7}}+\frac{\text{10}}{\text{3}}\right):\left(\text{12}\frac{\text{1}}{\text{3}}-\text{14}\frac{\text{2}}{\text{7}}\right)}\)

\(3,2.\frac{15}{16}-\left(75\%+\frac{2}{7}\right):\left(-1\frac{1}{28}\right)\)

\(\left(0,25+12,5-\frac{5}{16}\right):\left[12-\frac{7}{12}:\left(\frac{3}{8}-\frac{1}{12}\right)\right]\)

\(\left(\frac{-3}{5}+\frac{5}{11}\right):\frac{-3}{7}+\left(\frac{-2}{5}+\frac{6}{5}\right):\frac{-3}{7}\)

\(14,5-\frac{8}{9}:\left(35-34\frac{8}{9}\right).\frac{9}{8}\)

\(1\frac{1}{15}-\left(\frac{1}{15}+\frac{4}{9}:\frac{-2}{3}-\frac{28}{16}.\frac{6}{35}\right)-\frac{3}{10}\)

Tìm x 

\(\left(4,5-2x\right)\left(-3\frac{2}{3}\right)=\frac{11}{15}\)

\(\backslash34-x\backslash=\left(-3\right)^4\)

\(\left(4x^2-1\right)\left(\text{\x}\backslash-\frac{2}{3}\right)=0\)

\(\frac{3}{5}x-\frac{1}{2}\)\(x=\frac{-7}{20}\)

Thực hiện phép tính :

a, \(\sqrt{12\frac{1}{4}}.\left(-\frac{2}{7}\right)^2-\left[2,\left(4\right).2\frac{5}{11}\right]:(-\frac{42}{5})\)

b, \(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right)...\left(1-\frac{1}{2007}\right)\)

c, \(\frac{0,375-0,3+\frac{3}{11}+\frac{3}{12}}{-0,625+0,5-\frac{5}{11}-\frac{5}{12}}+\frac{1,5+1-0,75}{2,5+\frac{5}{3}-1,25}\)

Các bạn giải nhanh giúp mình nha! 

2. Tìm các tính chất đặc trưng của các phần tử thuộc tập hợp:

\(C=\left\{\text{2, 3, 5, 7, 11, 13}\right\}\)

\(D=\left\{1-\sqrt{3},1+\sqrt{3}\right\}\)

\(E=\left\{\text{1, 2, 5, 10, 17,26, 37}\right\}\)

\(F=\left\{\frac{1}{2},\frac{1}{6},\frac{1}{12},\frac{1}{20},\frac{1}{30}\right\}\)

\(G=\left\{\frac{2}{3},\frac{3}{8},\frac{4}{15},\frac{5}{24},\frac{6}{35}\right\}\)

Tính giá trị biểu thức

\(1.A=\frac{1}{5}+\frac{3}{17}-\frac{4}{3}+\left(\frac{4}{5}-\frac{3}{17}+\frac{1}{3}\right)-\frac{1}{7}+\left[\frac{-14}{30}\right]\)

\(2.B=\left(\frac{5}{8}-\frac{4}{12}+\frac{3}{2}\right)-\left(\frac{5}{8}+\frac{9}{13}\right)-\left[\frac{-3}{2}\right]+\frac{7}{-15}\)

\(3.C=\frac{5}{18}+\frac{8}{19}-\frac{7}{21}+\left(\frac{-10}{36}+\frac{11}{19}+\frac{1}{3}\right)-\frac{5}{8}\)

\(4.D=\frac{1}{9}-\left[\frac{-5}{23}\right]-\left(\frac{-5}{23}+\frac{1}{9}+\frac{25}{7}\right)+\frac{50}{14}-\frac{7}{30}\)

\(5.E=\frac{1}{13}+\left(\frac{-5}{18}-\frac{1}{13}+\frac{12}{17}\right)+\left(\frac{12}{17}+\frac{5}{18}+\frac{7}{5}\right)\)

\(6.F=\frac{15}{14}-\left(\frac{17}{23}-\frac{80}{87}+\frac{5}{4}\right)+\left(\frac{12}{17}-\frac{15}{14}+\frac{1}{4}\right)\)

\(7.G=\frac{1}{25}-\frac{4}{27}+\left(\frac{-23}{27}+\frac{-1}{25}-\frac{5}{43}\right)+\frac{5}{43}-\frac{4}{7}\)

\(8.H=\frac{4}{15}-\frac{23}{28}-\left(\frac{-23}{28}+\frac{-11}{15}-\frac{29}{27}\right)-\frac{2}{27}\)

\(9.K=\frac{1}{16}-\frac{5}{21}+\left(\frac{-1}{16}+\frac{-3}{5}-\frac{-5}{21}\right)+\frac{-2}{5}+\frac{3}{4}\)

\(10.L=\frac{7}{12}+\frac{15}{14}-\left(\frac{14}{22}+\frac{-1}{14}+\frac{5}{21}\right)-\frac{-5}{21}+\frac{3}{5}\)

1. \(\frac{1}{3}-\frac{3}{5}+\frac{5}{7}-\frac{7}{9}+\frac{9}{11}-\frac{11}{13}+\frac{11}{15}+\frac{11}{13}-\frac{9}{11}+\frac{7}{9}-\frac{5}{7}+\frac{3}{5}-\frac{1}{3}\)
2. \(\frac{-3}{4}.31\frac{11}{23}-0,75.8\frac{12}{28}\)
3. \(\left(2\frac{1}{3}+3\frac{1}{2}\right):\left(-4\frac{1}{6}+3\frac{1}{7}\right)+7\frac{1}{2}\)
4. \(4\frac{5}{9}:\left(-\frac{5}{7}\right)+5\frac{4}{9}:\left(-\frac{5}{7}\right)\)
5. \(\frac{2}{3}-4\left(\frac{1}{2}+\frac{3}{4}\right)\)
6. \(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right)....\left(1-\frac{1}{n+1}\right)n\in Z\)

\(a,1\frac{13}{15}.0,75-\left(\frac{8}{15}+0,25\right).\frac{24}{47}\)

\(b,5:\left(4\frac{3}{4}-1\frac{25}{28}\right)-1\frac{3}{8}:\left(\frac{3}{8}+\frac{9}{20}\right)\)

\(c,6\frac{5}{12}:2\frac{3}{4}+11\frac{1}{4}.\left(\frac{1}{3}-\frac{1}{5}\right)\)

\(d,\left(\frac{3}{5}+0,415-\frac{3}{200}\right).2\frac{2}{3}.0,25\)

\(e,\left(\frac{3}{8}+\frac{-3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)

\(g,1\frac{13}{15}.0,75-\left(\frac{11}{20}+25\%\right);\frac{7}{3}\)