Pls I need the answer immediately with steps plss

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

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?

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15