4-162 Find all integer pairs $(x, y)$ that satisfy the equation $x y=20-3 x+y$.


[Solution] The original equation can be transformed into
$$
(x-1)(y+3)=17 \text {, }
$$

Therefore, $\left\{\begin{array}{l}x-1=1, \\ y+3=17 ;\end{array}\right.$ or $\left\{\begin{array}{l}x-1=17, \\ y+3=1 ;\end{array}\right.$
or $\left\{\begin{array}{l}x-1=-1, \\ y+3=-17 ;\end{array}\right.$ or $\left\{\begin{array}{l}x-1=-17, \\ y+3=-1 .\end{array}\right.$

Solving these, the integer pairs that satisfy the equation are $(2,14),(18,-2),(0,-20),(-16,-4)$.