Can somebody plz help me and answer these questions right thx

(WILL MARK BRAINLIEST)

7x+8y=-18, 4x-9y=-3 solve the system of equations

An air conditioning system can circulate 350 cubic feet of air per minute. how many cubic yards of air can it circulate per minute?

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?