Đáp án:
a, `(5 - 2x)/3 = (4x - 1)/-5`
`⇒ -5(5 - 2x) = 3(4x - 1)`
` -25 + 10x = 12x - 3`
` 10x - 12x = -3 + 25`
` -2x = 22`
` x = 22 : -2 = -11`
b, `(10 - 2x)/6 = 27/(5 - x)` (ĐK : `x \neq -5`)
`(5 - x)/3 = 27/(5 - x)`
`⇒ (5 - x). (5 - x) = 27 . 3`
` (5 - x)^2 = 81`
` (5 - x)^2 = 9^2 = (-9)^2`
⇒\(\left[ \begin{array}{l}5 - x = 9\\5 - x = -9\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x = -4(TM)\\x = 14(TM)\end{array} \right.\)
Vậy `x \in { -4 ; 14}`
