contestada

A line is perpendicular to y =-1/3x +7
and intersects the point (4,2).
What is the equation of this
perpendicular line?

Respuesta :

The equation of the perpendicular line is y = 3x – 10.

Solution:

Equation of the line:

[tex]$y=-\frac{1}{3}x+7[/tex]

Slope of this line,

[tex]$m_1=\frac{-1}{3}[/tex]

If two lines are perpendicular, then the product of their slopes equal to –1.

[tex]$\text{Slope of perpendicular line}=\frac{-1}{\text{Slope of the line} }[/tex]

[tex]$\Rightarrow m_2=\frac{-1}{m_1 }[/tex]

[tex]$\Rightarrow m_2=\frac{-1}{\frac{-1}{3} }=\frac{3}{1}[/tex]

[tex]$\Rightarrow m_2=3[/tex]

The line passes through the point (4, 2).

Here, [tex]x_1=4, y_1=2[/tex]

Point-slope formula:

[tex]y-y_1=m(x-x_1)[/tex]

[tex]y-2=3(x-4)[/tex]

[tex]y-2=3x-12[/tex]

Add 2 on both sides of the equation.

y = 3x – 10

The equation of the perpendicular line is y = 3x – 10.