Solve algebraically:
3x + y = -21
x + y = -5

Which of the binomials below is a factor of this trinominal? x^2-13+30

The perimeter of a stage is 116 feet. it is 17 feet wide. how long is it?

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?