\(\frac{3x-5}{4}=0,3-9,11\)

\(\frac{3x-5}{4}=-8,81\)

\(3x-5=-35,24\)

\(3x=-30,24\)

\(x=-10,08\)

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\(-\frac{3}{5}:\frac{3}{14}+0,5x=12\)

\(-\frac{14}{5}+0,5x=12\)

\(0,5x=\frac{74}{5}\)

\(x=\frac{148}{5}\)

\(12.\left(\frac{3}{4}-5x\right)=12.\frac{3}{4}-12.5x=9-12.5x=9-60x\)

\(9-60x=\frac{4}{5}-3x\), Rồi bạn làm bước cuối, chuyển vế

\(2\frac{5}{7}+\frac{3}{14}-\frac{6}{7}+0,5+\frac{9}{14}=\frac{19}{7}+\frac{3}{14}-\frac{6}{7}+0,5+\frac{9}{14}\)

\(=\left(\frac{19}{7}-\frac{6}{7}\right)+\left(\frac{3}{14}+\frac{9}{14}\right)+0,5=1+\frac{6}{7}+0,5=\frac{33}{14}\)

\(A=\frac{0,375-0,3+\frac{3}{11}+\frac{1}{4}}{0,625+0,5-\frac{5}{11}-\frac{5}{12}}\)

\(=\frac{\frac{3}{8}-\frac{3}{10}+\frac{3}{11}+\frac{3}{12}}{\frac{5}{8}+\frac{5}{10}-\frac{5}{11}-\frac{5}{12}}\)

\(=\frac{3\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{5\left(\frac{1}{8}+\frac{1}{10}-\frac{1}{12}-\frac{1}{12}\right)}\)

\(=\frac{3.263.\frac{1}{1320}}{5.67.\frac{1}{1320}}=\frac{789.\frac{1}{1320}}{335,\frac{1}{1320}}=\frac{789}{335}\)

\(\frac{0,375-0,3+\frac{3}{11}+\frac{3}{12}}{-0,625+0,5-\frac{5}{11}-\frac{5}{12}}+\frac{1,5+1-0,75}{2,5+\frac{5}{3}-\frac{5}{4}}\)

\(=\frac{3\left(0,125-0,1+\frac{1}{11}+\frac{1}{12}\right)}{-5\left(0,125-0,1+\frac{1}{11}+\frac{1}{12}\right)}+\frac{3\left(0,5+\frac{1}{3}-\frac{1}{4}\right)}{5\left(0,5+\frac{1}{3}-\frac{1}{4}\right)}\)

\(=\frac{-3}{5}+\frac{3}{5}=0\)

P = 2005 : (   3(0,125 - 0,1 + 1/11 + 1/12)/-5(0,125 - 0,1 + 1/11 + 1/12)  *  5(0,5 + 1/3 - 0,25)/3(0,5 +1/3 - 0,25)   )

P = 2005 : (-3/5 * 5/3)

P = 2005 : (-1) = -2005

Chẳng cần máy tính cũng làm ra, có khi còn nhanh hơn máy tính 

\(A=\frac{3\left(\frac{1}{2}+\frac{1}{3}-\frac{1}{4}\right)}{5\left(\frac{1}{2}+\frac{1}{3}-\frac{1}{4}\right)}-\frac{3\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}{5\left(\frac{1}{8}-\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)}=\frac{3}{5}-\frac{3}{5}=0\)

đã bảo là = 0 -_- 

A=\(\frac{6}{5}\)