BT1: Tìm x, biết:
7) \(\left(\dfrac{2}{3}-\dfrac{3}{5}x\right)^3=\dfrac{-64}{125}\)
cho mk sửa lại
tacó:
\(\dfrac{-64}{125}=\left(\dfrac{-4}{5}\right)^3\)
suy ra\(\dfrac{2}{3}-\dfrac{3}{5}x=\dfrac{-4}{5}\)
\(\dfrac{3}{5}x=\dfrac{2}{3}-\dfrac{-4}{5}\)
\(\dfrac{3}{5}x=\dfrac{22}{15}\)
\(x=\dfrac{22}{15}:\dfrac{3}{5}\)
\(x=\dfrac{22}{9}\)
142 - (x.135) = 92
6) \(x^{20}+81x^{16}=0\)
1. Tính nhanh:
a. \(\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6}+\dfrac{5}{12}+\dfrac{19}{30}\)
b. \(\dfrac{1}{1x2}+\dfrac{1}{2x3}+\dfrac{1}{3x4}+...+\dfrac{1}{1998x1999}+\dfrac{1}{1999x2000}\)
Đây là toán lớp 5 nhé!
5) \(x^{13}=27x^{10}\)
tìm x:
a) \(\left(0,3+x\right).2\dfrac{1}{4}:x=-\dfrac{13}{40}\)
b) \(0,25.x-\dfrac{27}{8}.x=\dfrac{3}{4}\)
c) \(\dfrac{7}{8}+4\dfrac{1}{2}:x=-\dfrac{13}{40}\)
d) \(32\%-0,25:x=-3\dfrac{2}{5}\)
BT1: Tìm x, biết: 4) \(\dfrac{\left(x+1\right)^2}{2}=\dfrac{4}{x+1}\)
a) \(-8:\left(4\dfrac{1}{5}x+\dfrac{3}{10}\right)=4\dfrac{4}{9}\)
b) \(4\dfrac{2}{3}-\left(\dfrac{3}{5}:x\right)=-20\%\)
c) \(\left(\dfrac{13}{10}x-15\right).-\dfrac{5}{14}=3\)
d) \(\left(5,5x-44\right):\left(-\dfrac{3}{2}\right)=30\)
e) \(\dfrac{11}{14}:\left(2x+\dfrac{5}{7}\right)=-\dfrac{11}{18}\)
Cho 2 góc kề DOE và DOF, mỗi góc bằng 150 độ.Hỏi tia Od có phải tia phân giác của EOF không? Vì sao?
3) \(\dfrac{x-1}{2}=\dfrac{8}{x-1}\)
2) \(\left(x-3^2\right)^3=\left(3^3\right)^2\)
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