Question

设A.B.C.D为平面内四点,且AB=CD,A(3,1)B(-2,2)C(-1,4)

Answer 1

1.D(a,b)

3-(-2)=-1-a,1-2=4-b

a=-6,b=5

D(-6,5).

2.x-3=t(-6+2),y-1=t(5-2)

x-3=-4t,y-1=3t

(y-1)/3=-(x-3)/4

y=-3x/4+13/4.