Find the set of all points (x, y) such that the area of the triangle with vertices (0, 0), (6, 4) and (x, y) is 4.
Options:
A) 3
B) 9
C) 7
D) 8
E) 2
Explanation:   Area of a triangle if one of the point is (0, 0) = 12|(x1y2−x2y1)|12|(x1y2−x2y1)|   ⇒ 12|(6×y−4×x)|12|(6×y−4×x)| = 4   ⇒ 6y – 4x = 8   Answer: 8
<result>D</result>
Find the set of all points (x, y) such that the area of the triangle with vertices (0, 0), (6, 4) and (x, y) is 4.