\(\frac{a}{b}=\frac{c}{d}\Leftrightarrow\frac{a}{b}+1=\frac{c}{d}+1\Leftrightarrow\frac{a+b}{b}=\frac{c+d}{d}\) (dpcm)

Tìm x :

x - 0,27 = \(\frac{73}{100}\)

x           = \(\frac{73}{100}+0,27\)

x           = 1

Cậu P khó quá mik chưa nghĩ ra cách tính nhanh nhất !

Cậu tự giải nhé !

Hok tốt

\(x-0,27=\frac{\frac{73}{77}+\frac{73}{165}+\frac{73}{285}}{25\times\left(\frac{5}{84}+\frac{3}{180}+\frac{4}{285}\right)}.\)

\(x-0,27=\frac{\frac{146}{105}+\frac{73}{285}}{25\times\left(\frac{8}{105}+\frac{4}{285}\right)}\)

\(x-0,27=\frac{\frac{219}{133}}{25\times\frac{12}{133}}\)

\(x-0,27=\frac{\frac{219}{133}}{\frac{300}{133}}\)

\(x-0,27=0,73\)

\(x=0,73+0,27\)

\(x=1\)

x= 12/5 hoặc x=-12/5

\(\frac{x^2}{6}=\frac{24}{25}\)

\(x^2\cdot25=6\cdot24\)

\(x^2\cdot25=144\)

\(x^2=144:25\)

\(x=\pm\sqrt{\frac{12}{5}}\)

Nhầm bạn nhé

\(x=\pm\sqrt{\frac{144}{25}}\)

\(x=\pm\frac{12}{5}\)

1/

a) \(C=\frac{4}{7}.\frac{3}{5}.\frac{7}{4}.\left(-20\right).\frac{5}{6}\)

\(=\left(\frac{4}{7}.\frac{7}{4}\right).\left(\frac{3}{5}.\frac{5}{6}\right).\left(-20\right)\)

\(=\frac{1}{2}.\left(-20\right)\)

\(=-10\)

2/ \(B=\frac{2^2}{3}.\frac{3^2}{8}.\frac{4^2}{15}.\frac{5^2}{24}.\frac{6^2}{35}.\frac{7^2}{48}.\frac{8^2}{63}.\frac{9^2}{80}\)

\(=\frac{2.2}{1.3}.\frac{3.3}{2.4}.\frac{4.4}{3.5}.\frac{5.5}{4.6}.\frac{6.6}{5.7}.\frac{7.7}{6.8}.\frac{8.8}{7.9}.\frac{9.9}{8.10}\)

\(=\frac{2.3.4.5.6.7.8.9}{1.2.3.4.5.6.7.8}.\frac{2.3.4.5.6.7.8.9}{3.4.5.6.7.8.9.10}\)

\(=9.\frac{2}{10}=9.\frac{1}{5}=\frac{9}{5}\)

Ta có:

\(\frac{x^2}{6}=\frac{24}{25}\Leftrightarrow x^2.25=24.6\)

\(\Leftrightarrow x^2=\frac{24.6}{25}=\frac{144}{25}=5,76\)

\(\Leftrightarrow x=\sqrt{5,76}=2,4;x=-\sqrt{5,76}=-2,4\)

Vậy \(x=2,4\) hoặc \(x=-2,4\)

Bài 1:

\(\frac{7}{12}+\frac{-8}{15}=\frac{7}{12}-\frac{8}{15}=\frac{35}{60}-\frac{32}{60}=\frac{3}{60}=\frac{1}{20}\)

\(\frac{5}{12}+\frac{-8}{15}=\frac{5}{12}-\frac{8}{15}=\frac{25}{60}-\frac{32}{60}=\frac{-7}{60}\)

Bài 2:

\(a,x-23=-56\)

\(x=-56+23\)

\(x=-33\)

\(b,2x-36=24\)

\(2x=60\)

\(x=30\)

\(c,x-\frac{4}{5}=\frac{3}{2}\)

\(x=\frac{3}{2}+\frac{4}{5}=\frac{23}{10}\)

\(d,x-46=123\)

\(x=123+46=169\)

\(e,2x-25=-45\)

\(2x=-20\)

\(x=-10\)

\(f,x-\frac{2}{3}=-\frac{7}{5}\)

\(x=-\frac{7}{5}+\frac{2}{3}=-\frac{11}{15}\)

=.= hk tốt!!

a)\(M=\left(1-\frac{6-2x^3}{x^6-9}\right).\frac{4}{x^5+3x^2}:\left[\frac{6x^6-24}{x^9+6x^6+9x^3}:\left(\frac{3x^2}{2}+\frac{3}{x}\right)\right]\)

\(=\left(1-\frac{-2\left(x^3-3\right)}{\left(x^3+3\right)\left(x^3-3\right)}\right).\frac{4}{x^2\left(x^3+3\right)}:\left[\frac{6\left(x^3-2\right)\left(x^3+2\right)}{x^3\left(x^3+3\right)^2}:\frac{3x^3+6}{2x}\right]\)

\(=\left(\frac{x^3+3}{x^3+3}-\frac{-2}{x^3+3}\right).\frac{4}{x^2\left(x^3+3\right)}:\frac{12x\left(x^3-2\right)}{3x^3\left(x^3+3\right)^2\left(x^3+2\right)}\)

\(=\frac{4\left(x^3+3+2\right)}{x^2\left(x^3+3\right)^2}:\frac{12x\left(x^3-2\right)}{3x^3\left(x^3+3\right)^2\left(x^3+2\right)}=\frac{\left(x^3+5\right)\left(x^3+2\right)}{x^3-2}\)

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