(2) When a = 0, it is obviously parallel, and when a is not 0.

- 1/(2a)=(3a- 1)/a

a= 1/6

So a=0 or a= 1/6.

(3)a is all real numbers

6.-4a(a- 1)=- 1

a=( 1 √2)/2

7.-2m/4=- 1/(m+ 1)

m= 1，-2

Note that when m=-2, two straight lines coincide.

So when m= 1, it is parallel.

M is not equal to 1, and intersects when m is not equal to -2.

8.KAD=KBC=3/4, KEB =KCD=-3/4.

square