\(\dfrac{3\times4\times2\times14}{7\times4\times6}=\dfrac{3\times4\times2\times2\times7}{7\times4\times6}=\dfrac{6\times4\times2\times7}{7\times4\times6}=2\\ \dfrac{21\times18\times3\times4}{2\times6\times7\times9}=\dfrac{3\times7\times9\times2\times3\times2\times2}{2\times6\times7\times9}=\dfrac{3\times2}{1}=6\)

Áp dụng t/c của dãy tỉ số bằng nhau, ta có:

\(\frac{x-1}{3}=\frac{y-1}{4}=\frac{z+2}{5}=\frac{z-1+y-1+z+2}{3+4+5}=\frac{-36}{12}=-3\)

=> \(\hept{\begin{cases}\frac{x-1}{3}=-3\\\frac{y-1}{4}=-3\\\frac{z+2}{5}=-3\end{cases}}\)  => \(\hept{\begin{cases}x-1=-9\\y-1=-12\\z+2=-15\end{cases}}\) => \(\hept{\begin{cases}x=-8\\x=-11\\x=-13\end{cases}}\)

Vậy ...

1/4;1/39;1/38;1/35;1/3

\(a,\left(2x-1\right)^2-\left(2x+1\right)^2=4\left(x-3\right)\)

\(\Leftrightarrow4x^2-4x+1-4x^2-4x-1=4x-12\)

\(\Leftrightarrow-12x=-12\)

\(\Leftrightarrow x=1\)

\(b,\left(\frac{5x-7}{2}\right)=\left(\frac{16x+1}{7}\right)\)

\(\Leftrightarrow35x-49=32x+2\)

\(\Leftrightarrow3x=51\Leftrightarrow x=17\)

ĐKXĐ: x^2-4<>0

=>\(x\notin\left\{2;-2\right\}\)

2/10            9/20             1/10

k nha

2/10                                    9/20                                     1/10

MINH CUNG HOC LOP 5 DO NHA BAN

\(\frac{2}{10}\) \(\frac{9}{20}\) \(\frac{1}{10}\)

các bạn nhớ k cho mình nha