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\(x\cdot\left(\dfrac{3}{5}\right)^5=\left(\dfrac{3}{7}\right)^7\)
\(\Leftrightarrow x=\dfrac{3^7}{7^7}:\dfrac{3^5}{5^5}=\dfrac{3^7}{3^5}\cdot\dfrac{5^5}{7^7}\simeq0,034\)
Tìm x:
a) x+\(\dfrac{1}{3}=\dfrac{3}{4}\) b)x-\(\dfrac{2}{5}=\dfrac{5}{7}\) c)-x-\(\dfrac{2}{3}=-\dfrac{6}{7}\) d)\(\dfrac{4}{7}-x=\dfrac{1}{3}\)
Tìm x,y biết:
1) \(\dfrac{x}{5}=\dfrac{y}{7}\) và x+y = 48
2) \(\dfrac{x}{4}=\dfrac{y}{-7}\) và x-y=33
3) \(\dfrac{x}{y}=-\dfrac{2}{5}\) và x+y =12
4) \(\dfrac{x}{3}=\dfrac{y}{5}\) và 2x+4y=28
5) \(\dfrac{x}{y}=\dfrac{3}{16}\) và 3x-y=35
1) tìm x:
\(\left(\dfrac{1}{7}x-\dfrac{2}{7}\right)\left(-\dfrac{1}{5}x+\dfrac{3}{5}\right)\left(\dfrac{1}{3}x+\dfrac{4}{3}\right)=0\)
5. \(3-1\dfrac{1}{2}-x+\dfrac{5}{4}=2-\left|1\dfrac{1}{8}-\dfrac{5}{12}\right|\) 6. \(3\dfrac{1}{14}-5\dfrac{1}{3}-\dfrac{4}{7}+\dfrac{11}{21}=x-\dfrac{1}{2}\) 7. \(\dfrac{11}{-40}+\dfrac{4}{5}-\left|\dfrac{3}{4}-1\dfrac{5}{12}\right|=\dfrac{3}{20}-x\)
5. \(3-1\dfrac{1}{2}-x+\dfrac{5}{4}=2-\left|1\dfrac{1}{8}-\dfrac{5}{12}\right|\) 6. \(3\dfrac{1}{14}-5\dfrac{1}{3}-\dfrac{4}{7}+\dfrac{11}{21}=-\dfrac{1}{2}\) 7. \(\dfrac{11}{-40}+\dfrac{4}{5}-\left|\dfrac{3}{4}-1\dfrac{5}{12}\right|=\dfrac{3}{20}-X\)
1.\(\dfrac{x}{2}=\dfrac{y}{5}\)và x+y=21 2.7x=3y và x-y=16
3.\(\dfrac{x}{5}=\dfrac{y}{6}=\dfrac{z}{7}\)và x-y-z=36 4.x:y:z=3:5:7 và 2x+3y-z=-14
Câu 3. 
Câu 4. (\(\dfrac{4}{9}\)) \(^5\) . (\(\dfrac{3}{7}\))\(^{10}\) viết dưới dạng lũy thừa là?
Câu 5. \(\dfrac{x}{5}\) = \(\dfrac{y}{3}\) và x-y = 2. Giá trị x + y =?
Câu 6. x\(^2\) = 2. Số các giá trị của x thỏa mãn là?
Câu 7. 
rút gọn biểu thức khi \(\dfrac{-3}{5}\)<x<\(\dfrac{1}{7}\)
a,A=|x-\(\dfrac{1}{7}\)|-|x+\(\dfrac{3}{5}\)|+\(\dfrac{4}{5}\)
b, B=|-x+\(\dfrac{1}{7}\)|+|-x-\(\dfrac{3}{5}\)|-\(\dfrac{2}{6}\)
tim x , biet :
a) x + \(\dfrac{3}{10}\)= \(\dfrac{-2}{5}\)
b) x + \(\dfrac{5}{6}\) = \(\dfrac{2}{5}\) - \(\left(-\dfrac{2}{3}\right)\)
c) \(1\dfrac{2}{5}\) x + \(\dfrac{3}{7}\) = \(-\dfrac{4}{5}\)
d) \(\left[x+\dfrac{3}{4}\right]-\dfrac{1}{3}=0\)
e) \(\left[x+\dfrac{4}{15}\right]-\left[-3,75\right]=-\left[-2,15\right]\)
f) \(\left(x-2\right)^2=1\)
g) \(\left(2x-1\right)^3=-27\)
h) \(\dfrac{x-1}{-15}=\dfrac{-60}{x-1}\)
i) x : \(\left(\dfrac{-1}{2}\right)^3=\dfrac{-1}{2}\)
j) \(\left(\dfrac{3}{4}\right)^5.x=\left(\dfrac{3}{4}\right)^7\)
k) \(8^x:2^x=4\)
