Question

a. \(\dfrac{x-1}{27}=\dfrac{-1}{3}\)    b.\(\dfrac{x-3}{-25}=\dfrac{-4}{x-3}\)

Answer 1

a. \(\dfrac{x-1}{27}=\dfrac{-1}{3}\)

\(\Rightarrow3\left(x-1\right)=27.\left(-1\right)\)

\(3x-3=-27\)

\(3x=-27+3\)

\(3x=-24\)

\(x=-24:3\)

\(x=-8\)

b. \(\dfrac{x-3}{-25}=\dfrac{-4}{x-3}\)

\(\Rightarrow\left(x-3\right)^2=\left(-25\right).\left(-4\right)\)

\(\left(x-3\right)^2=100\)

\(\left(x-3\right)^2=10^2\)

\(\Rightarrow x-3=10\) hoặc \(x-3=-10\)

\(\Rightarrow x=10+3\) hoặc \(x=-10+3\)

\(\Rightarrow x=13\) hoặc \(x=-7\)

Answer 2

`a, (x-1)/27 = -1/3`

`<=> 3x - 3 = -27`

`<=> 3x = -24`

`<=> x = -8`

`b, Đk: x ne 3.`

`<=> (x-3)^2 = (-4) . (-25)`

`<=> (x-3)^2 = 100`

`<=>` \(\left[{}\begin{matrix}x-3=10\\x-3=-10\end{matrix}\right.\)

`<=>` \(\left[{}\begin{matrix}x=13\\x=-7\end{matrix}\right.\)