\(5\dfrac{2}{7}\times\dfrac{8}{11}+5\dfrac{2}{7}\times\dfrac{5}{11}-5\dfrac{2}{7}\times\dfrac{2}{11}\)
\(=5\dfrac{2}{7}\times\left(\dfrac{8}{11}+\dfrac{5}{11}-\dfrac{2}{11}\right)\)
\(=5\dfrac{2}{7}\times\dfrac{11}{11}\)
\(=5\dfrac{2}{7}\)
\(=\) \(\dfrac{37}{7}\)
Tính:
Q=2002:[\(\dfrac{0.4-\dfrac{2}{9}+\dfrac{2}{11}}{1,4-\dfrac{7}{9}+\dfrac{7}{11}}\).\(\dfrac{-1\dfrac{1}{6}+0,875-0,7}{\dfrac{1}{3}-0,25+\dfrac{1}{5}}\)]
1.Thực hiện phép tính sau một cách hợp lí:
A=\(\dfrac{\dfrac{2}{5}-\dfrac{2}{9}+\dfrac{2}{11}}{\dfrac{7}{5}-\dfrac{7}{9}+\dfrac{7}{11}}\) : \(\dfrac{\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{5}}{\dfrac{7}{6}-\dfrac{7}{8}+\dfrac{7}{10}}\)
2.Chứng minh rằng:Với mỗi x, y \(\in\) Q. Ta luôn có\(|x+y|\)\(\le\)\(|x|\)+\(|y|\)
Khi nào ta có đẳng thức?
thực hiện phép tính
a. \(\dfrac{11}{21}+\dfrac{-2}{7}+\dfrac{10}{21}+\left(-1\dfrac{1}{5}\right)+\dfrac{-5}{7}\)
\(b.\left(0.25\right)^5.\left(-5\dfrac{5}{9}\right).\left(-4\right)^5\)
\(c.\dfrac{3}{22}.19\dfrac{1}{7}+\dfrac{3}{22}.2\dfrac{6}{7}-\sqrt{36}\)
a,\(\dfrac{2}{3}+5\dfrac{3}{7}:2+\dfrac{9}{49}.\left(-7\right)+\dfrac{1}{12}.\left(-2\right)^4\)
b,\(2\dfrac{3}{4}.\left(-0,4\right)-1\dfrac{3}{5}.2,75+\left(-1,2\right):\dfrac{4}{11}\)
1) Tính hợp lý :
a) \(\dfrac{8^8.3^{14}}{9^6.2^{20}}\)
b) \(\dfrac{-1}{4}\) . \(13\dfrac{9}{11}\) - \(\dfrac{7}{20}\) - 0,25 . \(6\dfrac{2}{11}\)
c) \(\left(\dfrac{1}{5}\right)^5\) . 15\(^2\) - \(\dfrac{2^5.5}{2^7}\)
CÁC BẠN GIÚP MÌNH NHA
c.\(\dfrac{5^{11}}{7^{11}}.x=\left(\dfrac{5}{7}\right)^{12}.7\)
d.\(9^{x+2}+9^x-9^2.82=0\left(x\in N\right)\)
ĐỀ 2:
1. Tính:
A. \(\left(-\dfrac{2}{3}\right)^2+\left(-\dfrac{7}{8}\right)+\left(-\dfrac{11}{12}\right)\)
B. \(\left(\dfrac{-1}{3}\right)^2:\dfrac{1}{6}-2.\left(\dfrac{-1}{2}\right)^3\)\
C. \(\dfrac{-1}{5}-\left(\dfrac{1}{2}+\dfrac{3}{4}\right)^2:\dfrac{5}{8}\)
D. \(\left|\dfrac{-3}{2}+1,2\right|+1\dfrac{2}{3}:6\)
2. Tìm x, biết:
a. \(\dfrac{2}{3}x-\dfrac{1}{3}x=\dfrac{5}{12}\)
b. \(\left(x-\dfrac{12}{7}\right):1\dfrac{1}{5}=\dfrac{4}{7}\)
c. \(\dfrac{2}{5}+\left|x+1\right|=\dfrac{3}{4}\)
3. Tìm x, y biết:
a. \(\dfrac{x}{18}=\dfrac{y}{15}\)và x - y = -30
b. 7x = 9x và 10x - 8x = 68
c. \(\left(x-\dfrac{1}{2}\right)^{50}+\left(y+\dfrac{1}{3}\right)^{40}=0\)
* Lm nhanh nha
\(\dfrac{3}{8}\cdot27\dfrac{1}{5}-51\dfrac{1}{5}\cdot\dfrac{3}{8}+19\)
\(\dfrac{35\dfrac{1}{6}}{\left(\dfrac{-4}{5}\right)}-\dfrac{46\dfrac{1}{6}}{\left(\dfrac{-4}{5}\right)}\)
\(\dfrac{\left(\dfrac{-3}{4}+\dfrac{2}{5}\right)}{\dfrac{3}{7}+\dfrac{\left(\dfrac{3}{5}+\dfrac{-1}{4}\right)}{\dfrac{3}{7}}}\)
a) \(\left(1,25\right)^3.8^3\)
b) \(\left(\dfrac{-11}{9}\right)^4.\left(\dfrac{27}{22}\right)^4\)
c) \(\left(\dfrac{3}{7}+\dfrac{1}{2}\right)^2\)
d) \(\dfrac{5^4.20^4}{25^5.4^5}\)
