(X-X1)(Y2-Y1)=(Y-Y1)(X2-X1)
(X-1)(5-4)=(Y-4)(8-1)
X-1=7Y-28
X-7Y+27=0
BC:
(X-X1)(Y2-Y1)=(Y-Y1)(X2-X1)
(X-8)(-2-5)=(9-8)(Y-5)
Y-5=-7X+56
7X+Y-61=0
CK:
(X-X1)(Y2-Y1)=(Y-Y1)(X2-X1)
(X-9)(-3+2)=(Y+2)(2-9)
-1(X-9)=-7(Y+2)
(X-9)=7(Y+2)
X-7Y-23=0
AK:
(X-X1)(Y2-Y1)=(Y-Y1)(X2-X1)
(X-1)(-3-4)=(Y-4)(2-1)
-7(X-1)=(Y-4)
-7X+7-Y+4=0
7X+Y-11=0
Вот по-моему и все
