Here's a "formula" that can be used to find a new point :
New Point ' = [ Old Point - Dilation Center ] *Scale Factor + Dilation Center
Note that (a , b) - (c, d) = (a - c, b - d)
(a, b) + (c , d) = ( a + c, b + d) and
(a, b) * S = (Sa, Sb)
So.....to transform (0, - 4) as follows
New Point' = [ ( 0 - 4) - ( 2, - 7) ] * 3 + ( 2, -7) =
[ ( -2, 3) ] * 3 + (2, -7) =
(- 6, 9) + ( 2, - 7) =
(-4, 2)
You can compute the other points yourself