The points (3a, 0), (0, 3b) and (a, 2b) are
Vertices of an equilateral triangle
Vertices of an isosceles triangle
Vertices of a right angled isosceles triangle
Collinear
I1=√(3a)2+(3b)2=3√a2+b2
I2=√a2+b2=√a2+b2
I3=√(2a)2+(2b)2=2√a2+b2⇒I1=I2+I3
Hence the points are collinear.
Show that the points (a, 0), (0, b) and (3a, -2b) are collinear. Also find the equation of the line containing them.