1: Congruent figures are exactly the same as each other.
3: Apply the translation, and then apply the dilation to your translation image.
7: The vertical transformation is y -> 2y + 1.
8: This transformation needs a reflection and a dilation.
18: Similar means exactly the same shape (even if the size is different).
20: Visualize making something bigger and then turning it, versus turning it and then making it bigger.