Question

Which set of points are collinear?
a.)A(-1,5); B(2,6); C(4,7)
b.)A(0,0); B(1/2,3); C(1,5)
c.)A(-4,-2); B(0,-4); C(2,-5)
when i graph them they all look straight to me but the one I pick is
A(-1,5); B(2,6); C(4,7)

Answer 1

To be collinear, line segments have to be parallel, and a point must be common

for your choice
slopeAB=1/3, slope BC=1/2
so they are not parallel

b) slopeAB = 3/(1/2) = 6 , slope BC = 2/(1/2) = 4
not parallel

c) slopeAB = -2/4 = -1/2 , slope BC = -1/2
so the correct choice is c)