how to find affine transform between triangles ?

I Have 6 triangles. 3 triangle are in A and 3 triangle in Aprim. triangle1: points 1,2,3 of A triangle2: points 4,5,6 of A triangle3: points 7,8,9 of A triangle5:points 1,2,3 of Aprim triangle6:points 4,5,6 of Aprim triangle7:points 7,8,9 of Aprim

 x , y coordinate of A are :
A.x=[x1 x2 x3;x4 x5 x6;x7 x8 x9].
A.y=[y1 y2 y3;y4 y5 y6;y7 y8 y9]
x , y coordinate of Aprime are :
Aprim.x=[xp1 xp2 xp3;xp4 xp5 xp6;xp7 xp8 xp9]
Aprim.y=[yp1 yp2 yp3;yp4 yp5 yp6;yp7 yp8 yp9]

I Want to find affine transforms that map each triangle of A to triangle of Aprim in this way: t1 is affin transform that map triangle1 of A to triangle1 of Aprim. t2 is affin transform that map triangle2 of A to triangle2 of Aprim.t3 is affin transform that map the points triangle3 of A to triangle3 of Aprim. can anybody help me to write matlab code of it to find t1,t2,t3?