\(a,x^2-3x-4=0\\ \Leftrightarrow x^2+x-4x-4=0\\ \Leftrightarrow x\left(x+1\right)-4\left(x+1\right)=0\\ \Leftrightarrow\left(x-4\right)\left(x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x-4=0\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-1\end{matrix}\right.\\ c,3x^2-10x+3=0\\ \Leftrightarrow3x^2-9x-x+3=0\\ \Leftrightarrow3x\left(x-3\right)-\left(x-3\right)=0\\ \Leftrightarrow\left(3x-1\right)\left(x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}3x-1=0\\x-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=3\end{matrix}\right.\)
a)
\(x^2-3x-4=0\\ < =>x^2-4x+x-4=0\\ < =>x\left(x-4\right)+\left(x-4\right)=0\\ < =>\left(x-4\right)\left(x+1\right)=0\\ < =>\left[{}\begin{matrix}x-4=0< =>x=4\\x+1=0< =>x=-1\end{matrix}\right.\)
c)
\(3x^2-10x+3=0\\ < =>3x^2-9x-x+3=0\\ < =>3x\left(x-3\right)-\left(x-3\right)=0\\ < =>\left(x-3\right)\left(3x-1\right)=0\\ < =>\left[{}\begin{matrix}x-3=0< =>x=3\\3x-1=0< =>x=\dfrac{1}{3}\end{matrix}\right.\)
`a)x^2-3x-4=0`
`<=>x^2-4x+x-4=0`
`<=>(x-4)(x+1)=0`
`<=>[(x=4),(x=-1):}`
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`c)3x^2-10x+3=0`
`<=>3x^2-9x-x+3=0`
`<=>(x-3)(3x-1)=0`
`<=>[(x=3),(x=1/3):}`
