\(a,\Leftrightarrow x^2+14x+49-x^2+3x=12\\ \Leftrightarrow17x=-37\Leftrightarrow x=-\dfrac{37}{17}\\ b,\Leftrightarrow x^2-x-2x+2=0\\ \Leftrightarrow\left(x-1\right)\left(x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\)
a) \(x^2+2x7+49-x^2+3x=12\Leftrightarrow17x=-37\Leftrightarrow x=\dfrac{-37}{17}\)
b) \(x^2-2x-x+2=0\Leftrightarrow x\left(x-2\right)-\left(x-2\right)=0\Leftrightarrow\left(x-1\right)\left(x-2\right)=\left(0\right)\Leftrightarrow x=1,x=2\)
`a,`
`(x+7)^2-x(x-3)=12`
`<=>x^2+14x+49 - x^2 +3x=12`
`<=> 17x =-37`
`<=>x=(-37)/17`
Vậy `x=(-37)/17`
`b,`
`x^2-3x+2=0`
`<=>x^2-2x-x+2=0`
`<=>x(x-2)-(x-2)=0`
`<=>(x-2)(x-1)=0`
giải ra `x=2,x=1`
Vậy `x=2,x=1`
