\(\dfrac{x-1}{10}+\dfrac{x-2}{11}+\dfrac{x-3}{12}=\dfrac{x-4}{13}+\dfrac{x-5}{14}+\dfrac{x-6}{15}\)
Dựa vào t/c dãy tỉ số = nhau ta có:
\(\dfrac{x-1+x-2+x-3}{10+11+12}=\dfrac{x-4+x-5+x-6}{13+14+15}\)
\(\dfrac{3x-6}{33}=\dfrac{3x-15}{42}\)
\(42\left(3x-6\right)=33\left(3x-15\right)\)
\(126x-252=99x-495\)
\(126-99x=594-252\)
\(27x=342\)
\(x=\dfrac{38}{3}\)
BT3: Tìm x, biết
13) \(\left(-1\dfrac{1}{5}+x\right):\left(-3\dfrac{3}{5}\right)=\dfrac{-7}{4}+\dfrac{1}{4}:\dfrac{1}{8}\)
14) \(\dfrac{11}{13}-\left(\dfrac{5}{42}-x\right)=-\left(\dfrac{15}{28}-\dfrac{11}{13}\right)\)
tìm x:
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) \(\dfrac{11}{14}:\left(2x+\dfrac{5}{7}\right)=-\dfrac{11}{18}\)
tìm x
\([\dfrac{6:\dfrac{3}{5}-1\dfrac{1}{16}.\dfrac{16}{7}}{4\dfrac{1}{5}-\dfrac{10}{11}+5\dfrac{2}{11}}-\dfrac{\left(\dfrac{3}{20}+\dfrac{1}{2}-\dfrac{1}{5}\right).\dfrac{12}{49}}{3\dfrac{1}{3}+\dfrac{2}{9}}].x=2\dfrac{23}{96}\)
\(\left(2x-3\right)\left(6-2x\right)=0\)
\(\dfrac{1}{3}x+\dfrac{2}{5}\left(x-1\right)=0\)
\(\left(3x-1\right)\left(-\dfrac{1}{2}x+5\right)=0\)
\(\dfrac{x}{5}=\dfrac{2}{3}\)
\(\dfrac{x}{3}-\dfrac{1}{2}=\dfrac{1}{5}\)
\(\dfrac{x}{5}-\dfrac{1}{2}=\dfrac{6}{10}\)
\(\dfrac{x+3}{15}=\dfrac{1}{3}\)
\(\dfrac{x-12}{4}=\dfrac{1}{2}\)
1. Tìm x, biết
a. \(\dfrac{1}{2}x-\dfrac{3}{4}x-\dfrac{7}{3}=\dfrac{-5}{6}\)
b. \(Ix-\dfrac{1}{6}I+\dfrac{-5}{12}=\dfrac{4}{7}.\dfrac{14}{48}\)
tìm x:
a)\(\left(x+\dfrac{1}{2}\right).\left(\dfrac{2}{3}-2x\right)=0\)
b) \(\left(x.6\dfrac{2}{7}+\dfrac{3}{7}\right).2\dfrac{1}{5}-\dfrac{3}{7}=-2\)
c) \(x.3\dfrac{1}{4}+\left(\dfrac{-7}{6}\right).x-1\dfrac{2}{3}=\dfrac{5}{12}\)
d) \(5\dfrac{8}{17}:x+\left(-\dfrac{4}{17}\right):x+3\dfrac{1}{7}:17\dfrac{1}{3}=\dfrac{4}{11}\)
Bài 1: Tìm x, biết:
a, \(\left(x+\dfrac{1}{4}-\dfrac{1}{3}\right):\left(2+\dfrac{1}{6}-\dfrac{1}{4}\right)=\dfrac{7}{46}\)
b, \(\dfrac{13}{15}-\left(\dfrac{13}{21}+x\right).\dfrac{7}{12}=\dfrac{7}{10}\)
Bài 2: Thực hiện phép tính:
a, \(\left(2\dfrac{5}{6}+1\dfrac{4}{9}\right):\left(10\dfrac{1}{12}-9\dfrac{1}{2}\right)\)
b, 1\(\dfrac{5}{18}-\dfrac{5}{18}.\left(\dfrac{1}{15}+1\dfrac{1}{12}\right)\)
c, \(-\dfrac{1}{7}.\left(9\dfrac{1}{2}-8,75\right):\dfrac{2}{7}+0,625:1\dfrac{2}{3}\)
Tìm x biết:
\(\dfrac{3}{4}.x+\dfrac{1}{5}=\dfrac{1}{6}\)
b)(\(4\dfrac{1}{2}-\dfrac{2}{5}x\)):\(\dfrac{7}{4}=\dfrac{11}{14}\)
Bài 1: Tính ( hợp lý nếu có thể)
A=\(\dfrac{-3}{8}\)+\(\dfrac{12}{25}\)+\(\dfrac{5}{-8}\)+\(\dfrac{2}{-5}\)+\(\dfrac{13}{25}\)
B=\(\dfrac{-3}{15}\)+(\(\dfrac{2}{3}\)+\(\dfrac{3}{15}\))
C=\(\dfrac{-5}{21}\)+(\(\dfrac{-16}{21}\)+1)
D=(\(\dfrac{-1}{6}\)+\(\dfrac{5}{-12}\))+\(\dfrac{7}{12}\)
E=\(\dfrac{1}{3}\)x\(\dfrac{4}{5}\)+\(\dfrac{1}{3}\)x\(\dfrac{6}{5}\)+\(\dfrac{2}{3}\)
F=\(\dfrac{-5}{6}\)x\(\dfrac{4}{19}\)+\(\dfrac{-7}{12}\)x\(\dfrac{4}{12}\)-\(\dfrac{40}{47}\)
Bài 2: Tìm x,biết:
a) x + \(\dfrac{2}{3}\) = \(\dfrac{4}{5}\)
b) x - \(\dfrac{2}{3}\) = \(\dfrac{7}{21}\)
c) -x - \(\dfrac{3}{4}\) =\(\dfrac{-8}{11}\)
d) \(\dfrac{11}{12}\) - (\(\dfrac{2}{5}\) + x) = \(\dfrac{2}{3}\)
