If the points A (-2,1),B(a,b)and C(4,-1 )are collinear and A -B=1 find the value of A and B

If the points A (-2,1),B(a,b)and C(4,-1 )are collinear and A -B=1 find

1.	If the points A (-2,1),B(a,b)and C(4,-1 )are collinear and A -B=1 find the value of A and B
Answer» A=5/4and B=1/4