Answer 2,3,4,9 with numerical expression

Olivia uses the work below to determine 55% of 720 which explains the error in olivia’s solution

David is spreading mulch on a triangular area of his flower bed. the coordinates of the vertices of the area are (1, 3), (9, 3), and (4, 6). what is the area of the triangle if each square has an area of 3 square feet?

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?