`(4x + 2) + 2(5x - 2)^2 - 2(4x + 1)(5x - 2) = 0`
`(4x + 2) + 2(5x - 2)(5x - 2) - 2(4x + 1)(5x - 2) = 0`
`2( 5x - 2 ) ( 5x + 1 ) = 0`
`⇔`$\left[\begin{matrix} 5x-2=0\\ 5x+1=0\end{matrix}\right.$
`⇔`$\left[\begin{matrix} 5x=2\\ 5x=-1\end{matrix}\right.$
`⇔`$\left[\begin{matrix} x=2/5\\ x=-1/5\end{matrix}\right.$
(TM)