\(\frac{3}{8}.x+\frac{11}{4}=-0,25\)
\(a,1\frac{13}{15}.0,75-\left(\frac{8}{15}+0,25\right).\frac{24}{47}\)
\(b,5:\left(4\frac{3}{4}-1\frac{25}{28}\right)-1\frac{3}{8}:\left(\frac{3}{8}+\frac{9}{20}\right)\)
\(c,6\frac{5}{12}:2\frac{3}{4}+11\frac{1}{4}.\left(\frac{1}{3}-\frac{1}{5}\right)\)
\(d,\left(\frac{3}{5}+0,415-\frac{3}{200}\right).2\frac{2}{3}.0,25\)
\(e,\left(\frac{3}{8}+\frac{-3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)
\(g,1\frac{13}{15}.0,75-\left(\frac{11}{20}+25\%\right);\frac{7}{3}\)
Bài 1: Thực hiện phép tính(tính nhanh nếu có thể)
a) \(\frac{-4}{5}:\frac{8}{7}\)
b) \(\frac{-3}{8}.\frac{7}{9}+\frac{-3}{8}.\frac{2}{9}+0,25\)
c) 15\(\frac{3}{7}-\left(2\frac{4}{9}+11\frac{3}{7}\right)\)
Bài 2: Tìm x, biết:
a) x+\(\frac{2}{3}=\frac{5}{6}\)
b) 2\(\frac{3}{5}-8x=\left(\frac{1}{7}-\frac{1}{8}\right).56\)
Tính hợp lý
a. \(\frac{1}{4}\)x\(13\frac{9}{11}\)+ 0,25 x \(6\frac{2}{11}\)
b. \(\frac{7}{8}\)- \(2\frac{5}{6}\)+ 1,25
a,\(\frac{1}{4}.13\frac{9}{11}+0,25.6\frac{2}{11}\)
\(=0,25.\left(13\frac{9}{11}+6\frac{2}{11}\right)\)
\(=0,25.20\)
\(=5\)
b,\(\frac{7}{8}-2\frac{5}{6}+1,25\)
\(=\frac{7}{8}-\frac{17}{6}+\frac{5}{4}\)
\(=\frac{42}{48}-\frac{136}{48}+\frac{60}{48}\)
\(=\frac{42-136+60}{48}=-\frac{34}{48}=-\frac{17}{24}\)
a) =0,25.152/11+0,25.68/11
=0,25.( 152/11+68/11)
=0,25.20
=5
\(5\frac{6}{11}x+8\frac{9}{11}x+2\frac{3}{11}=3\frac{4}{11}x-\frac{8}{11}\)
\(5\frac{6}{11}x+8\frac{9}{11}x+2\frac{3}{11}=3\frac{4}{11}x-\frac{8}{11}\)
Tìm x biết:
a) \(\frac{-3}{5}.y=\frac{21}{10}\)
b) \(y:\frac{3}{8}=-1\frac{31}{33}\)
c) \(1\frac{2}{5}.y+\frac{3}{7}=\frac{-4}{5}\)
d) \(\frac{-11}{12}.y+0,25=\frac{5}{6}\)
Tìm x biết:
a) \(\frac{-3}{5}.y=\frac{21}{10}\)
b) \(y:\frac{3}{8}=-1\frac{31}{33}\)
c) \(1\frac{2}{5}.y+\frac{3}{7}=\frac{-4}{5}\)
d) \(\frac{-11}{12}.y+0,25=\frac{5}{6}\)
a) \(\frac{-3}{5}.y=\frac{21}{10}\)
\(y=\frac{21}{10}:\frac{-3}{5}\)
\(y=\frac{-7}{2}\)
vậy \(y=\frac{-7}{2}\)
b) \(y:\frac{3}{8}=-1\frac{31}{33}\)
\(y:\frac{3}{8}=\frac{-64}{33}\)
\(y=\frac{-64}{33}.\frac{3}{8}\)
\(y=\frac{-8}{11}\)
vậy \(y=\frac{-8}{11}\)
c) \(1\frac{2}{5}.y+\frac{3}{7}=\frac{-4}{5}\)
\(\frac{7}{5}.y+\frac{3}{7}=\frac{-4}{5}\)
\(\frac{7}{5}.y=\frac{-4}{5}-\frac{3}{7}\)
\(\frac{7}{5}.y=\frac{-43}{35}\)
\(y=\frac{-43}{35}:\frac{7}{5}\)
\(y=\frac{-43}{49}\)
vậy \(y=\frac{-43}{49}\)
d) \(\frac{-11}{12}.y+0,25=\frac{5}{6}\)
\(\frac{-11}{12}.y=\frac{5}{6}-0,25\)
\(\frac{-11}{12}.y=\frac{7}{12}\)
\(y=\frac{7}{12}:\frac{-11}{12}\)
\(y=\frac{-7}{11}\)
vậy \(y=\frac{-7}{11}\)
\(3\frac{1}{4}\div\frac{8}{5}=0,25\div x\)
3 1/4:8/5=0,25:x
13/4:8/5=1/4:x
1/4:x =65/12
x =1/4:65/12
x =3/65
\(3\frac{1}{4}:\frac{8}{5}=0,25:x\)
\(\frac{13}{4}:\frac{8}{5}=\frac{1}{4}:x\)
\(\frac{65}{32}=\frac{1}{4}:x\)
\(x=\frac{1}{4}:\frac{65}{32}\)
\(x=\frac{8}{65}\)
Vậy \(x=\frac{8}{65}\)
Tính bằng cách hợp lý: A= \(\frac{\frac{3}{11}+1-\frac{3}{7}}{3+\frac{9}{11}-\frac{9}{7}}\)-\(\frac{\frac{1}{3}+0,25-\frac{1}{5}+0,125}{\frac{7}{6}+\frac{7}{8}-0,7+\frac{7}{16}}\)
Ta có: \(A=\frac{\frac{3}{11}+1-\frac{3}{7}}{3+\frac{9}{11}-\frac{9}{7}}-\frac{\frac{1}{3}+0,25-\frac{1}{5}+0,125}{\frac{7}{6}+\frac{7}{8}-0,7+\frac{7}{16}}\)
\(=\frac{3\left(\frac{1}{11}+\frac{1}{3}-\frac{1}{7}\right)}{9\left(\frac{1}{3}+\frac{1}{11}-\frac{1}{7}\right)}-\frac{2\left(\frac{1}{6}+\frac{1}{8}-\frac{1}{10}+\frac{1}{16}\right)}{7\left(\frac{1}{6}+\frac{1}{8}-\frac{1}{10}+\frac{1}{16}\right)}\)
\(=\frac{3}{9}-\frac{2}{7}=\frac{1}{3}-\frac{2}{7}=\frac{7}{21}-\frac{6}{21}=\frac{1}{21}\)
Vậy \(A=\frac{1}{21}\)