\(\frac{25}{2}\%+x=\frac{100}{3}\%\)

                    \(x=\frac{100}{3}\%-\frac{25}{2}\%\)

                    \(x=\frac{200}{6}\%-\frac{75}{6}\%\)

                     \(x=\frac{125}{6}\%\)

= 125 / 6

\(12\frac{3}{7}\%+12\frac{5}{7}\%=\frac{176}{7}\%\)

\(\frac{3}{12}+\frac{2}{4}-\frac{2}{12}\)

\(=\frac{3}{12}+\frac{6}{12}-\frac{2}{12}\)

\(=\frac{3+6-2}{12}\)

\(=\frac{7}{12}\)

\(\frac{3}{12}+\frac{2}{4}-\frac{2}{12}\)

\(=\frac{3}{12}+\frac{6}{12}-\frac{2}{12}\)

\(=\frac{9}{12}-\frac{2}{12}\)

\(=\frac{7}{12}\)

\(\frac{3}{12}+\frac{2}{4}-\frac{2}{12}\)

\(=\frac{3}{12}+\frac{6}{12}-\frac{2}{12}\)

\(=\frac{7}{12}\)

  60   +   90    x    \(\frac{3}{5}\)

= 60     +         54

= 114

\(60+90\times\frac{3}{5}\)

\(=60+54=114\)

60+90 x 3/5=114

2\(\frac{2}{12}\)+ X = \(\frac{5}{7}\)+ \(\frac{8}{12}\)

\(\frac{13}{6}\)+ X=\(\frac{29}{21}\)

X= \(\frac{29}{21}\)- \(\frac{13}{6}\)

X=\(\frac{-11}{14}\)

\(|2^2_{12}\)\(+x=\frac{5}{7}+\frac{8}{12}\)

\(2+x=\frac{5}{7}+\frac{1}{2}\)

\(2+x=\frac{17}{14}\)

\(x=\frac{17}{14}-2\)

\(x=\frac{-11}{14}\)

\(2\frac{2}{12}+x=\frac{5}{7}+\frac{8}{12}\)

\(\frac{26}{12}+x=\frac{29}{21}\)

               x  = \(\frac{29}{21}-\frac{26}{12}\)

              x  = \(\frac{-11}{14}\)

ket bn nha cau

mk dng ko co bn olm

\(\frac{1}{4}.\frac{2}{6}.\frac{3}{8}.\frac{4}{10}.\frac{5}{12}.....\frac{30}{62}.\frac{31}{64}=4^x\)

\(\Leftrightarrow\)\(\frac{1.2.3.4.5.....30.31}{4.6.8.10.12.....62.64}=4^x\)

\(\Leftrightarrow\)\(\frac{2.3.4.5.....30.31}{2\left(2.3.4.5.....30.31\right).64}=4^x\)

\(\Leftrightarrow\)\(\frac{1}{128}=4^x\)

\(\Leftrightarrow\)\(2^{2x}=2^{-7}\) ( trong sgk có phần đọc thêm nói về cái này nhé ) 

\(\Leftrightarrow\)\(2x=-7\)

\(\Leftrightarrow\)\(x=\frac{-7}{2}\)

Vậy \(x=\frac{-7}{2}\)

Chúc bạn học tốt ~ 

\(\frac{1}{4}.\frac{2}{6}.\frac{3}{8}.\frac{4}{10}.\frac{5}{12}.....\frac{30}{62}.\frac{31}{64}=4^x\)

\(=\frac{1}{2.2}.\frac{2}{2.3}.\frac{3}{2.4}.\frac{4}{2.5}.\frac{5}{2.6}....\frac{30}{2.31}.\frac{31}{2.32}=4^x\)

\(=\frac{1}{2^{31}.2^5}=4^x\)

\(=\frac{1}{2^{36}}=4^x\)

\(=\frac{1}{2^{36}}=2^{2x}\)

\(=2^{-36}=2^{2x}\)

\(=-36=2.x\)

\(x.2=-36\)

\(x=-36:2\)

\(x=-18\)

\(2\frac{4}{3}+\frac{4}{12}=\frac{2.3+4}{3}+\frac{4}{12}=\frac{10}{3}+\frac{4}{12}=\frac{40}{12}+\frac{4}{12}=\frac{44}{12}=\frac{11}{3}\)

\(2\frac{4}{3}=\frac{10}{3}\)

\(\frac{10}{3}+\frac{4}{12}=\frac{120}{36}+\frac{12}{36}\)

\(=\frac{132}{36}=\frac{22}{6}=\frac{11}{3}\)

mình nè

= 2x4/3x4 + 3x3/4x3 +3/12=8/12+9/12+3/12=8+9+3/12=20/12=5/3

dễ sợ thiệt

Mấy bạn dùng mấy cái này để xin đúng

a) $\frac{1}{6} \times \frac{2}{3} = \frac{{1 \times 2}}{{6 \times 3}} = \frac{2}{{18}} = \frac{1}{9}$                            

b) $\frac{6}{5} \times \frac{3}{8} = \frac{{6 \times 3}}{{5 \times 8}} = \frac{{18}}{{40}} = \frac{9}{{20}}$

c) $\frac{4}{3} \times \frac{8}{9} = \frac{{4 \times 8}}{{3 \times 9}} = \frac{{32}}{{27}}$        

d) $\frac{5}{{12}} \times \frac{{12}}{5} = \frac{{5 \times 12}}{{12 \times 5}} = \frac{{60}}{{60}} = 1$