$$\left. \begin{array} { l } { A = 7 x ( x ^ { 2 } + 3 x - 1 ) } \\ { B = \sqrt { 5 } ( 3 x - \sqrt { 5 } ) } \end{array} \right.$$
$x=\frac{\sqrt{5}\left(B+5\right)}{15}$
$A=\frac{7\sqrt{5}\left(B+5\right)\left(\left(B+5\right)^{2}+9\sqrt{5}\left(B+5\right)-45\right)}{675}$
