# Thread: [SOLVED] equation of line

1. ## [SOLVED] equation of line

Find an equation for the line with the given properties.

Perpendicular to the line y=1/3x + 6; containing the point (2,-2)

2. Originally Posted by Ashley189
Find an equation for the line with the given properties.

Perpendicular to the line y=1/3x + 6; containing the point (2,-2)
would have slope:

$\displaystyle m=-3$

$\displaystyle (a, b)=(2, -2)$

so

$\displaystyle y+2=-3(x-2)$ from $\displaystyle y-b=m(x-a)$.

$\displaystyle \Box$

3. Originally Posted by GaloisTheory1
would have slope:

$\displaystyle m=-3$

$\displaystyle (a, b)=(2, -2)$

so

$\displaystyle y+2=-3(x-2)$ from $\displaystyle y-b=m(x-a)$.

$\displaystyle \Box$
I get it a little bit, but I'm still kinda confused.

4. Originally Posted by Ashley189
Find an equation for the line with the given properties.

Perpendicular to the line y=1/3x + 6; containing the point (2,-2)

You know the line is perpendicular to y=1/3x+6 so we can find its gradient .

using the formula $\displaystyle m_1m_2=-1$ , we find that its gradient is -3.

This line passes through point (2,-2)

Using this formula , $\displaystyle y-y_1=m(x-x_1)$

Substitute appropriately , we get $\displaystyle y-(-2)=-3(x-2)$ and simplify it ,