Official solution
(2x)2y = 4e2x-2y
2y\[\ell \]n2x = \[\ell \]n4 + 2x - 2y
y = \[{{x + \ell n2} \over {1 + \ell n2x}}\]
y ' = \[{{\left( {1 + \ell n2x} \right) - \left( {x + \ell n2} \right){1 \over x}} \over {{{\left( {1 + \ell n2x} \right)}^2}}}\]
y '\[{\left( {1 + \ell n2x} \right)^2} = \left[ {{{x\ell n2x - \ell n2} \over x}} \right]\]