10. Find the midpoint of the line segment that joins each pair of points:
a) (Ϫ3, Ϫ7) and (2, 5) c) (Ϫa, Ϫb) and (a, b)
b) (0, 0) and (Ϫ2, 6) d) (2a, 2b) and (2c, 2d)
Points A and B have symmetry with respect to the
origin O. Find the coordinates of B if A is the point:
a) (3, 4) c) (a, 0)
b) (0, 2) d) (b, c)