Q:

Write the equation of a line that is perpendicular to the given line and that passes through the given point.–x + 5y = 14; (–5, –2)

Accepted Solution

A:
Greetings and Happy Holidays!

1) Perpendicular to [tex]-x+5y=14[/tex]
In order for lines to be perpendicular, their slopes must be negative reciprocals.
Example of slopes with negative reciprocals: 5 and [tex] \frac{-1}{5} [/tex]

First, rearrange the equation into slope y-intercept form:
[tex]-x+5y=14[/tex]

[tex]5y=x+14[/tex]

[tex] \frac{5y}{5}=\frac{x+14}{5} [/tex]

[tex]y=\frac{1}{5}x+\frac{14}{5}[/tex]

The slope of the equation is: \frac{1}{5}

The negative reciprocal formula: [tex] (m_{1})(m_{2})=-1[/tex]

Solve for the negative reciprocal: 
[tex] \frac{1}{5}m_{2}=-1[/tex]

Divide both sides by [tex]\frac{1}{5}[/tex]
[tex]\frac{\frac{1}{5}m_{2} }{ \frac{1}{5}} = \frac{-1}{ \frac{1}{5}}[/tex]

[tex]m_{2}=(-1)(\frac{5}{1})[/tex]

[tex]m_{2}=(\frac{-5}{1})[/tex]

[tex]m_{2}=-5[/tex]

The slope of the new line is: -5

2) Passes through (-5,-2)

Create an equation with the slope discovered in slope y-intercept form.
[tex]y=-5x+b[/tex]

Input the point the line passes through.
[tex](-2)=-5(-5)+b[/tex]

Solve for b (the y-intercept).
[tex]-2=-5(-5)+b[/tex]

Multiply.
[tex]-2=25+b[/tex]

Add -25 to both sides.
[tex](-2)+(-25)=b[/tex]

[tex]-27=b[/tex]

The y-intercept is equal to -27

The Equation of the line is:
[tex]y=-5x-27[/tex]

I hope this helped!
-Benjamin