What equation can I make from this information?

This is so hard and it’s for a test

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?

If /is a line of symmetry, plot the partner points for the ones shown. noch 6 5 4 -3 -2 -1