\(-5\left(x+2\right)=45-95\)

\(-5\left(x+2\right)=-50\)

\(x+2=10\)

\(x=8\)

a \(\left(25\times4\right)\times\left(125\times8\right)=100\times1000=100000\)

b \(17\times\left(173-73\right)=17\times100=1700\)

c \(46\times5=230\)

a \(\dfrac{7}{8}:\dfrac{49}{6}+\dfrac{4}{28}=\dfrac{7}{8}\times\dfrac{6}{49}+\dfrac{4}{28}=\dfrac{3}{28}+\dfrac{4}{28}=\dfrac{7}{28}=\dfrac{1}{4}\)

b \(\dfrac{16}{5}\times\dfrac{25}{8}+\dfrac{18}{5}\times20=10+72=82\)

\(27x^2-3=0\)

\(\Leftrightarrow27x^2=3\)

\(\Leftrightarrow x^2=\dfrac{1}{9}\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=-\dfrac{1}{3}\end{matrix}\right.\)

\(-x=\dfrac{5}{4}+2\)

\(-x=\dfrac{5}{4}+\dfrac{8}{4}\)

\(-x=\dfrac{13}{4}\)

\(x=-\dfrac{13}{4}\)

Were not

\(a\) \(\dfrac{21}{25};\dfrac{60}{81};\dfrac{19}{29}\)

\(b\) \(\dfrac{15}{6};\dfrac{2004}{1999};1;\dfrac{12}{15};\dfrac{3}{5};\dfrac{6}{14}\)

Tìm BCNN ( 56 , 24 , 72 ) : 504

A