$$
\begin{aligned}
& y^2+4 x=y^2+31 \\
& \left(x^2+4 x+4\right)-y^2=31+4 \\
& (x+2)^2-y^2=35 \\
& (x+2+y)(x+2-y)=35
\end{aligned}
$$

$\because x . y$ 为正数

$$
\begin{aligned}
& \therefore x+2+y>0, x+2+y>x+2-y \\
& \therefore\left\{\begin{array} { l }
{ x + 2 + y = 3 5 } \\
{ x + 2 – y = 1 }
\end{array} \text { 威 } \left\{\begin{array}{l}
x+2+y=7 \\
x+2-y=5
\end{array}\right.\right. \\
& \therefore\left\{\begin{array} { l }
{ x = 1 6 } \\
{ y = 1 7 }
\end{array} \text { 或 } \left\{\begin{array}{l}
x=4 \\
y=1
\end{array}\right.\right.
\end{aligned}
$$

$\therefore x$. y值为 16.17 成4.1.