Question

Use the distance formula to show that the points A(1,-1),B(6,4) and C(4,2) are collinear

Answer 1

to prove it prove that distance between ac+cb =ab ............ statement1
distance between ab=root(5^2+5^2)=5root(2)
distance between bc=root(2^2+2^2)=2root(2)
distance between ab=root(3^2+3^2)=3root(2)
we can see that 5root(2)=2root(2)+3root(2)
thus statement 1 is proved

Answer 2

to prove it prove that distance between ac+cb =ab statement1

distance between ab=root(5^2+5^2)=5root(2)

distance between bc=root(2^2+2^2)=2root(2)

distance between ab=root(3^2+3^2)=3root(2)

we can see that 5root(2)=2root(2)+3root(2)

thus statement 1 is proved