Question

The set of points R(-1, 1), S(2, 4), T(6, 8) are collinear. true or false

Answer 1

R, S and T are collinear if they are in the same exact line. 

It is enough to show that slope of RS is equal (or not) to the slope of ST, 

slope of RS$=m_R_S= \frac{4-1}{2-(-1)}= \frac{3}{3}=1$

slope of ST$=m_S_T= \frac{8-4}{6-2}= \frac{4}{4}=1$

the lines through R, S and S, T have the same slope so the three points are collinear.

Answer: TRUE