\(-1\dfrac{1}{2}-x=\dfrac{-2}{3}+0,75\)
\(\dfrac{-3}{2}-x=\dfrac{1}{12}\Rightarrow x=\dfrac{-19}{12}\)
\(\left|\dfrac{4}{5}-x\right|-\dfrac{1}{10}=\dfrac{2}{5}\)
\(\Leftrightarrow\left|\dfrac{4}{5}-x\right|=\dfrac{1}{2}\)
\(\Leftrightarrow\dfrac{4}{5}-x=\dfrac{1}{2}\Rightarrow x=\dfrac{3}{10}\)
\(\Leftrightarrow\dfrac{4}{5}-x=-\dfrac{1}{2}\Rightarrow x=\dfrac{13}{10}\)
Bài 1:
a) \(\left[\dfrac{3}{20}-\dfrac{1}{5}x\right].1\dfrac{2}{3}=1\dfrac{1}{4}\)
b)\(\dfrac{-2}{3}.x+\dfrac{1}{5}=\dfrac{3}{10}\)
c)\(\dfrac{-2}{3} \)-\(\dfrac{1}{3}\left(2x-7\right)=\dfrac{3}{2}\)
tìm x biết
a) \(\dfrac{2x-3}{3}+-\dfrac{3}{2}=\dfrac{5-2x}{6}-\dfrac{1}{2}\)
b) \(\left(3x-\dfrac{1}{2}\right).\left(3-\dfrac{1}{2}x\right).\left(1+\dfrac{3}{4}:x\right)=0\)
c) \(\left(3-\dfrac{9}{10}-|x+2|\right):\left(\dfrac{19}{20}-1-\dfrac{2}{3}\right)+\dfrac{4}{5}=1\)
Tìm x, biết :
a) \(\left(\dfrac{31}{20}-\dfrac{26}{45}\right).\dfrac{-36}{35}< x< \left(\dfrac{51}{56}+\dfrac{8}{21}+\dfrac{1}{3}\right).\dfrac{8}{13}\)
b) \(\dfrac{-3}{5}.x=\dfrac{1}{4}+0,75\)
c) \(\left(\dfrac{1}{7}-\dfrac{1}{3}\right).x=\dfrac{28}{3}.\left(\dfrac{1}{4}-\dfrac{1}{7}\right)\)
d) \(\dfrac{5}{7}.x=\dfrac{9}{8}-0,125\)
e)\(\left(\dfrac{2}{11}+\dfrac{1}{3}\right).x=\left(\dfrac{1}{7}-\dfrac{1}{8}\right).56\)
Tìm số x , biết
a) \(\dfrac{2}{3}x-\dfrac{3}{2}x=\dfrac{5}{12}\)
b) \(\dfrac{2}{5}+\dfrac{3}{5}.\left(3x-3,7\right)=-\dfrac{53}{10}\)
c) \(\dfrac{7}{9}:\left(2+\dfrac{3}{4}x\right)+\dfrac{5}{9}=\dfrac{23}{27}\)
d) \(\dfrac{-2}{3}.x+\dfrac{1}{5}=\dfrac{3}{10}\)
e) \(\left|x\right|-\dfrac{3}{4}=\dfrac{5}{3}\)
f) \(\left|2x-\dfrac{1}{3}\right|+\dfrac{5}{6}=1\)
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) \(5\dfrac{8}{17}:x+\left(-\dfrac{4}{17}\right):x+3\dfrac{1}{7}:17\dfrac{1}{3}=\dfrac{4}{11}\)
a, \(\dfrac{5}{2}-3\left(\dfrac{1}{3}-x\right)=\dfrac{1}{4}-7x\)
b,\(60\%.x+\dfrac{2}{3}.x=\dfrac{1}{3}.6\dfrac{1}{3}\)
c, \(\left(\dfrac{9}{2}.x-2x\right).\left(-1\dfrac{4}{7}\right)=\dfrac{11}{4}\)
d,\(\left(x+\dfrac{5}{6}\right).2\dfrac{2}{5}-1\dfrac{1}{4}=35\%\)
Câu 1: Tìm x biết
a) \(-\dfrac{2}{3}\)\(\left(x-\dfrac{1}{4}\right)\) = \(\dfrac{1}{3}\left(2x-1\right)\) b) \(\dfrac{1}{5}.2^x+\dfrac{1}{3}.2^{x+1}=\dfrac{1}{5}.2^7+\dfrac{1}{3}.2^8\)
Câu 2: a) Cho A = \(\dfrac{1}{2}.\dfrac{3}{4}.\dfrac{5}{6}......\dfrac{9999}{10000}\)
So sánh A vs 0,01
b) Chứng tỏ rằng: \(\left[\left(1+2+3+....+n\right)-7\right]⋮̸10\)
Bài 1: Thực hiện phép tính
a) \(\left(\dfrac{3}{8}+\dfrac{-3}{4}+\dfrac{7}{12}\right):\dfrac{5}{6}+\dfrac{1}{2}\)
b) \(\dfrac{1}{2}+\dfrac{3}{4}-\left(\dfrac{3}{4}-\dfrac{4}{5}\right)\)
c) \(6\dfrac{5}{12}:2\dfrac{3}{4}+11\dfrac{1}{4}.\left(\dfrac{1}{3}\dfrac{1}{5}\right)\)
d)\(\left(\dfrac{7}{8}-\dfrac{3}{4}\right).1\dfrac{1}{3}-\dfrac{2}{7}.\left(3,5\right)^2\)
e)\(\left(\dfrac{3}{5}+0,415-\dfrac{3}{200}\right).2\dfrac{2}{3}.0,25\)
f)\(\dfrac{5}{16}:0,125-\left(2\dfrac{1}{4}-0,6\right).\dfrac{10}{11}\)
g) \(0,25:\left(10,3-9,8\right)-\dfrac{3}{4}\)
h)\(1\dfrac{13}{15}.0,75-\left(\dfrac{11}{20}+20\%\right):\dfrac{7}{3}\)
i)\(\dfrac{\left(\dfrac{1}{2-0,75}\right).\left(0,2-\dfrac{2}{5}\right)}{\dfrac{5}{9}-1\dfrac{1}{12}}\)
k)\(\dfrac{\dfrac{2}{3}+\dfrac{2}{7}-\dfrac{1}{14}}{-1-\dfrac{3}{7}+\dfrac{3}{28}}\)
Bài 2: Tính bằng cánh hợp lí
A=\(0,7.2\dfrac{2}{3}.20.0,375.\dfrac{5}{28}\)
B=\(\left(9\dfrac{30303}{80808}+7\dfrac{303030}{484848}\right)+4,03\)
C=\(\left(9,75.21\dfrac{3}{7}+\dfrac{39}{4}.18\dfrac{4}{7}\right).\dfrac{15}{78}\)
D=\(10101.\left(\dfrac{5}{111111}+\dfrac{5}{222222}-\dfrac{4}{3.7.11.13.37}\right)\)
\(\left(2x-3\right)\left(6-2x\right)=0\)
\(\dfrac{1}{3}x+\dfrac{2}{5}\left(x-1\right)=0\)
\(\left(3x-1\right)\left(-\dfrac{1}{2}x+5\right)=0\)
\(\dfrac{x}{5}=\dfrac{2}{3}\)
\(\dfrac{x}{3}-\dfrac{1}{2}=\dfrac{1}{5}\)
\(\dfrac{x}{5}-\dfrac{1}{2}=\dfrac{6}{10}\)
\(\dfrac{x+3}{15}=\dfrac{1}{3}\)
\(\dfrac{x-12}{4}=\dfrac{1}{2}\)
