7 . 5x : (9 - 6\(\dfrac{13}{21}\)) = 2\(\dfrac{13}{25}\)
7 . 5x : 2\(\dfrac{8}{21}\) = 2\(\dfrac{13}{25}\)
7 . 5x = 2\(\dfrac{13}{25}\) . 2\(\dfrac{8}{21}\)
7 . 5x = 6
5x = 6 : 7
5x = 6 . \(\dfrac{1}{7}\)
5x = \(\dfrac{6}{7}\)
a) \(7,5:\left(9-6\dfrac{13}{21}\right)=2\dfrac{13}{25}\) (câu này tính)
b) \(\dfrac{\left(1,16-x\right).5,25}{\left(10\dfrac{5}{9}-7\dfrac{1}{4}\right).2\dfrac{2}{17}}=75\%\)
c) \(\left(\dfrac{1}{1.3}+\dfrac{1}{3.5}+...+\dfrac{1}{19.21}\right).420-\left[0,4.\left(7,5-2,5x\right)\right]:0,25=212\)
Tìm x ϵ Z, biết:
a, \(\dfrac{111}{37}\)< x< \(\dfrac{91}{13}\)
b, \(\dfrac{-84}{14}< 3x< \dfrac{108}{9}\)
Cảm ơn nha!
a, \(\dfrac{x-2}{15}+\dfrac{x-3}{14}+\dfrac{x-4}{13}+\dfrac{x-5}{12}=4\)
b, \(\dfrac{x+1}{19}+\dfrac{x+2}{18}+\dfrac{x+3}{17}+...+\dfrac{x+18}{2}+18=0\)
Cảm ơn khi đã giúp mình
Áp dụng tính chất các phép tính và quy tắc dấu ngoặc để tính giá trị các biểu thức sau :
\(A=11\dfrac{3}{13}-\left(2\dfrac{4}{7}+5\dfrac{3}{13}\right)\)
\(B=\left(6\dfrac{4}{9}+3\dfrac{7}{11}\right)-4\dfrac{4}{9}\)
\(C=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}-\dfrac{9}{11}+1\dfrac{5}{7}\)
\(D=0,7.2\dfrac{2}{3}.20.0,375.\dfrac{5}{28}\)
\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{3}-0,25-\dfrac{1}{12}\right)\)
Tìm x biết
\(\dfrac{29}{30}\) - ( \(\dfrac{13}{23}\) + x ) = \(\dfrac{7}{69}\)
tính
a) (\(2\dfrac{5}{6}+1\dfrac{4}{9}\)):(\(10\dfrac{1}{12}\)-9\(\dfrac{1}{2}\))
b) \(\dfrac{0,8:\left(\dfrac{4}{5}:1,25\right)}{0,64-\dfrac{1}{25}}\)
c) \(\dfrac{\left(100-\dfrac{2}{25}\right):\dfrac{4}{7}}{\left(6\dfrac{5}{9}-3\dfrac{1}{4}\right).2\dfrac{2}{27}}\) + (1,2 . 0,5) : \(\dfrac{3}{5}\)
Tìm số nguyên x, y biết:
a, \(\dfrac{-1}{5}\)≤ \(\dfrac{x}{8}\)≤ \(\dfrac{1}{4}\)
b, \(\dfrac{4}{x-6}\)= \(\dfrac{y}{24}\)= \(\dfrac{-12}{18}\)
c, \(\dfrac{x+46}{20}\)=x \(\dfrac{2}{5}\)
Tìm x, biết:
a, \(\left(2\dfrac{3}{4}-1\dfrac{4}{5}\right)x=1\)
b, \(x^2-9\) \(3-5x=0\)
c, \(\left|3x-1\right|+2\dfrac{3}{4}=3\dfrac{1}{16}\)
Tìm x
a) \(\left[\left(6\dfrac{3}{7}-\dfrac{0,75.x-2}{0,35}\right).2,8+1,75\right]:0,05=2,35\)
b) \(\dfrac{3}{5}-\dfrac{2}{7}< \dfrac{2}{3}.x+\dfrac{3}{4}< \dfrac{1}{2}+\dfrac{7}{9}\)