` b) ` Ta có:
` \frac{x-1}{2} = \frac{2x-2}{4} `
` \frac{y-2}{3} = \frac{3y-6}{9} `
Áp dụng tính chất dãy tỉ số bằng nhau, ta có:
` \frac{2x - 2}{4} = \frac{3y-6}{9} = \frac{z-3}{4} = \frac{(2x - 2) + (3y - 6) - (z - 3)}{4 + 9 - 4} = \frac{2x - 2 + 3y - 6 - z + 3}{9} = \frac{2x + 3y - z - 2 - 6 + 3}{9} = \frac{50 - 5}{9} = 45/9 = 5 `
` => ` \(\left[ \begin{array}{l}\frac{2x-2}{4}=5⇔x=\frac{5.4+2}{2}=11\\\frac{3y-6}{9}=5⇔y=\frac{5.9+6}{3}=17\\\frac{z-3}{4}=5⇔z=5.4+3=23\end{array} \right.\)
