Precalculus (6th Edition)

Published by Pearson
ISBN 10: 013421742X
ISBN 13: 978-0-13421-742-0

Chapter 2 - Graphs and Functions - 2.1 Rectangular Coordinates and Graphs - 2.1 Exercises - Page 193: 31

Answer

$$\color {blue}{\bf\text{No, the points are not collinear}}$$

Work Step by Step

For clarity lets start by naming our points: $A=(0,9)$ $B=(-3,-7)$ $C=(2,19)$ First, we'll use the distance formula for the distance between each pair of points: $d(P,Q)=\sqrt{(x_{P}-x_{Q})^2+(y_{P}-y_{Q})^2}$ $AB= \sqrt{(0-(-3))^2+(9-(-7))^2}$ $AB= \sqrt{(3^2+16^2}$ $AB= \sqrt{(9+256}$ $AB= \sqrt{265}$ $AC= \sqrt{(0-2)^2+(9-19)^2}$ $AC= \sqrt{(-2)^2+(-10)^2}$ $AC= \sqrt{4+100}$ $AC= \sqrt{400}$ $BC= \sqrt{(-3-2)^2+(-7-19)^2}$ $BC= \sqrt{(-5)^2+(-26)^2}$ $BC= \sqrt{25+676}$ $BC= \sqrt{701}$ Now that we have the lengths of the sides, $AB=\sqrt{265}$, $AC= \sqrt{400}$, $BC=\sqrt{701}$, we can see if the two shortest equal the longest. $\sqrt{265}+ \sqrt{400}=\sqrt{701}$ Which is $\bf \text{false}$, so: $$\color {blue}{\bf\text{No, the points are not collinear}}$$
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