a)x2-7x+10=0
\(\Leftrightarrow x^2-2x-5x+10=0\)
\(\Rightarrow x\left(x-2\right)-5\left(x-2\right)=0\)
\(\Rightarrow\left(x-5\right)\left(x-2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-5=0\\x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=2\end{matrix}\right.\)
Vậy \(x=5\) hoặc \(x=2\)
b) 36x2-49=0
\(\Leftrightarrow\left(6x\right)^2-7^2=0\)
\(\Rightarrow\left(6x+7\right)\left(6x-7\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}6x+7=0\\6x-7=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}6x=-7\\6x=7\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-7}{6}\\x=\dfrac{7}{6}\end{matrix}\right.\)
Vậy \(x=\dfrac{-7}{6}\) hoặc \(x=\dfrac{7}{6}\)
a) x2-7x+10=0
=> x2-2x-5x+10=0
=> x(x-2)-5(x-2)=0
=> x(x-2)=0 -> hoặc x =0 hoặc x-2=0-> x=2
hoặc -5(x-2)=0 -> x=2
vậy x= 0 hoặc x= 2
b) 36x2-49=0
=> (6x)2-72=0
=> (6x-7)(6x+7)=0
=>hoặc 6x-7=0 -> 6x=7 -> x=7:6
hoặc 6x+7=0->6x=-7-> x = 6:7
vậy x=7:6 hoặc x=6:7
