Question

Which of the following equations represents the perpendicular bisector of WX graphed below?

Answer 1

The coordinates of the 2 given points are W(-5, 2), and X(5, -4).

First, we find the midpoint M using the midpoint formula:

$\displaystyle{ M_{WX}= (\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2} )= (\frac{-5+5}{2}, \frac{2+(-4)}{2} )=(0, -1).$

Nex, we find the slope of the line containing M, perpendicular to WX. We know that if m and n are the slopes of 2 parallel lines, then mn=-1.

The slope of WX is $\displaystyle{ m= \frac{y_2-y_1}{x_2-x_1}= \frac{2-(-4)}{-5-5}= \frac{6}{-10}= -\frac{3}{5}$.

Thus, the slope n of the perpendicular line is $\displaystyle{ \frac{5}{3}$.

The equation of the line with slope $\displaystyle{ n= \frac{5}{3}$ containing the point M(0, -1) is given by:

$\displaystyle{ y-(-1)=\frac{5}{3}(x-0)$

$\displaystyle{ y+1= \frac{5}{3}x$

$\displaystyle{ 3y+3=5x$

$\displaystyle{ 5x-3y-3=0$

Answer: 5x-3y-3=0