If area of `triangle ABC` is 12 square units and vertices are `A (x, 2), B (4, - 1)` and `C (- 3, 7)`, then find the value of x.

If area of a triangle is 0 square units, its vertices will be…………… .

For the triangle ABC whose vertices are A (-2, 3), B (4, - 3) and C (6, 5), find the equation of : the altitude from A.

Find the value of k’ if the area of the triangle is 4 sq. units and vertices are (-2,0),(0,4) and (0, k).

For the triangle ABC whose vertices are A (-2, 3), B (4, - 3) and C (6, 5), find the equation of : the perpendicular bisector of the side BC.