x2-x-4x+4=0
x(x-1)-4(x-1)=0
(x-1)(x-4)=0
\(\orbr{\begin{cases}x-1=0\\x-4=0\end{cases}}\)
\(\orbr{\begin{cases}x=1\\x=4\end{cases}}\)
x2 - 5x + 4 = 0
=> x2 - x - 4x + 4 = 0
=> (x2 - x) - (4x - 4) = 0
=> x(x - 1) - 4(x - 1) = 0
=> (x - 4)(x - 1) = 0
=> x - 4 = 0 hoặc x - 1 = 0
=> x = 4 hoặc x = 1
vậy_
\(x^2-5x+4=0\)\(=>x^2-2x.\frac{5}{2}+\left(\frac{5}{2}\right)^2-\frac{9}{4}=0\)\(=>\left(x-\frac{5}{2}\right)^2-\frac{9}{4}=0\)\(=>\left(x-\frac{5}{2}\right)^2=\frac{9}{4}>0\)\(=>\orbr{\begin{cases}x-\frac{5}{2}=\frac{9}{4}\\x-\frac{5}{2}=\frac{-9}{4}\end{cases}}\)\(=>\orbr{\begin{cases}x=\frac{19}{4}\\x=\frac{1}{4}\end{cases}}\)
Vậy \(x=\frac{19}{4}\) và \(x=\frac{1}{4}\)
\(x^2-5x+4=0\)
\(x^2-4x-x+4=0\)
\(x\left(x-4\right)-\left(x-4\right)=0\)
\(\left(x-4\right)\left(x-1\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-4=0\\x-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=4\\x=1\end{cases}}}\)