a) \(\left(x-3\right)\left(4-5x\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x-3=0\\4-5x=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=3\\x=\frac{4}{5}\end{array}\right.\)
b) \(\left(x-1\right)^2=25\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x-1=5\\x-1=-5\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=6\\x=-4\end{array}\right.\)
a)(x-3)(4-5x)\(\Leftrightarrow\)\(\left[\begin{array}{nghiempt}x-3=0\\4-5x=0\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=3\\x=\frac{4}{5}\end{array}\right.\)
Vậy x=3 và \(\frac{4}{5}\)
b) \(\left(x-1\right)^2=25\Rightarrow\begin{cases}x-1=5\\x-1=-5\end{cases}\)
\(\Rightarrow\begin{cases}x=6\\x=-4\end{cases}\)
Vậy x=-4 và 6
\(a.\)
\(\left(x-3\right)\left(4-5x\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x-3=0\\4-5x=0\end{array}\right.\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=3\\x=0,8\end{array}\right.\)
Vậy : \(x\in\left\{0,8;3\right\}\)
\(b.\)
\(\left(x-1\right)^2=25\)
\(\Leftrightarrow\left(x-1\right)^2=\left(\pm5\right)^2\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x-1=-5\\x-1=5\end{array}\right.\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=-4\\x=6\end{array}\right.\)
Vậy : \(x\in\left\{-4;6\right\}\)
