Dilatation is the transformation that produces and image that is the same shape as the original, but different size. So, in order to find the dilatation of a triangle, you need to multiplícate by a scale factor the given coordinates. An ex: A'(0,2), B'(2,-1), and C'(-2,-2) , lets say that you are going to múltiple by 2, the formula would be (2x, 2y), and the results will be A'(0,4) B'(4,-2), C' (-4,-4).
If you are looking for the expanded version, this is it. It is also possible to group either an a from (a^2 + 2b) or a b from (2ab + b^2). Hope this helps!