\(A=\sqrt{9.7}-2\sqrt{25.7}+\sqrt{9.7.4}-\frac{1}{7}\sqrt{4.7}\)

\(=3\sqrt{7}-10\sqrt{7}+6\sqrt{7}-\frac{2}{7}\sqrt{7}\)

\(=\frac{-9}{7}\sqrt{7}\)

Nếu đúng tk nhé

a = \(\sqrt{63}-2\sqrt{175}+\sqrt{252}-\frac{1}{7}\sqrt{28}\)

  = \(\sqrt{\frac{4}{7}}\left(1,5-5+3-1\right)\)

 =  \(-1,5\sqrt{\frac{4}{7}}\)

được nhé bạn

`84 / 252 = [ 84 : 84 ] / [ 252 : 84 ] = 1 / 3`

Bằng 1/3

\(\dfrac{112}{324}=\dfrac{28}{81}\)

\(\dfrac{112}{324}=\dfrac{112:4}{324:4}=\dfrac{28}{81}\)

`252/2772=[252:252]/[2772:252]=1/11`

\(\dfrac{1}{11}\)

\(\dfrac{1}{11}\)

\(\dfrac{60}{252}=\dfrac{60:12}{252:12}=\dfrac{5}{21}\)

\(\frac{96}{324}=\frac{96:12}{324:12}=\frac{8}{27}\)

\(\frac{113344}{175168}=\frac{113344:10304}{175168:10304}=\frac{11}{17}\)

ta có 252=2².3².7

BCNN?(-142,252)=2².3².7=252

=\(\dfrac{-142}{252}\)

tick cho mk 

dấu mũ ngược đời v

\(\frac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}\)

=\(\frac{3.2^3}{5^2}\)=24/25

\(\frac{3600-75}{8400-175}=\frac{3525}{8225}=\frac{3}{7}\)

Theo đề bài ta có

\(\frac{a+15}{b}=\frac{a}{b}+\frac{15}{b}=\frac{7}{6}\Rightarrow\frac{3}{4}+\frac{15}{b}=\frac{7}{6}.\)

\(\Rightarrow\frac{15}{b}=\frac{7}{6}-\frac{3}{4}=\frac{5}{12}\Rightarrow b=36\)

\(\Rightarrow\frac{a}{b}=\frac{a}{36}=\frac{3}{4}\Rightarrow a=27\)