a) \(x^2-2x=0\)
\(x\left(x-2\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x-2=0\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}}\)
b) \(x^2-7x+12=0\)
\(x^2-4x-3x+12=0\)
\(\left(x^2-3x\right)-\left(4x-12\right)=0\)
\(x\left(x-3\right)-4\left(x-3\right)=0\)
\(\left(x-4\right)\left(x-3\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-4=0\\x-3=0\end{cases}\Rightarrow\orbr{\begin{cases}x=4\\x=3\end{cases}}}\)
a) \(x^2-2x=0\)
\(x\left(x-2\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x-2=0\end{cases}}\) \(\Rightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}\)
b) \(x^2-7x+12=0\)
\(x^2-3x-4x+12=0\)
\(\left(x^2-3x\right)-\left(4x-12\right)=0\)
\(x\left(x-3\right)-4\left(x-3\right)=0\)
\(\left(x-3\right)\left(x-4\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\x-4=0\end{cases}}\) \(\Rightarrow\orbr{\begin{cases}x=3\\x=4\end{cases}}\)
a) x^2 - 2x = 0
x ( x - 2 ) = 0
=> x = 0 hoặc x - 2 = 0
x = 0 hoặc x = 2
b) x^2 - 7x + 12 = 0
x^2 -3x - 4x + 12 = 0
x(x - 4) - 3(x - 4) = 0
(x - 4).(x - 3) = 0
=> x - 4 = 0 hoặc x - 3 = 0
x = 4 hoặc x = 3
a)x^2-2x=0
=>x(x-2)=0
=>x=0,x=2
b)x^2-7x+12=0
=>[(x)^2-2*x*7/2+(7/2)^2+17/2=0
=>(x-7/2)^2+17/2=0
=>(x-7/2)^2=0
=>x=7/2
a) \(x^2-2x=0\)\(\Leftrightarrow x\left(x-2\right)=0\)\(\Leftrightarrow\orbr{\begin{cases}x=0\\x-2=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}\)
Vậy \(x=0\)hoặc \(x=2\)
b) \(x^2-7x+12=0\)\(\Leftrightarrow x^2-3x-4x+12=0\)\(\Leftrightarrow\left(x^2-3x\right)-\left(4x-12\right)=0\)
\(\Leftrightarrow x\left(x-3\right)-4\left(x-3\right)=0\)\(\Leftrightarrow\left(x-3\right)\left(x-4\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-3=0\\x-4=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=4\end{cases}}\)
Vậy \(x=3\)hoặc \(x=4\)
