Find the area of the triangle whose vertices are:

P(0, 0), Q(6, 0) and R(4, 3)

Find the area of the triangle whose vertices are:

A(-2, 4), B(2, -6) and C(5, 4)

Find the area of the triangle whose vertices are:

A(-8, -2), B(-4, -6) and C(-1, 5)

Find the area of the triangle whose vertices are:

P(1, 1), Q(2, 7) and R(10, 8)

Use determinants to show that the following points are collinear.

A(2, 3), B(-1, -2) and C(5, 8)