Tìm x biết: (2x-1)^2 - (4x+1)(x-3) = -3

* Hướng dẫn giải

$\begin{array}{l}{\left(2\mathrm{x}-1\right)}^2-\left(4\mathrm{x}+1\right)\left(\mathrm{x}-3\right)=-3\\ 4{\mathrm{x}}^2-4\mathrm{x}+1-4{\mathrm{x}}^2+11\mathrm{x}+3=-3\\ -4\mathrm{x}+11\mathrm{x}=-3-3-1\\ 7\mathrm{x}=-7\\ \mathrm{x}=-1\end{array}$