(-1, 3) and perpendicular to y = -1/3x + 7.

Question

mikezack123 · Answer

y = 3x - 12

 y = 3x + 6

 y = 3x - 6

 y = 3x

anonymous · Answer

You need an equation that passes through (-1,3)?

mikezack123 · Answer

@AlwaystheBookworm yes

mikezack123 · Answer

and that is perpendicular to that equation above.

mathstudent55 · Answer

What is the slope of the given line?

anonymous · Answer

Oh, well you could simply just plug it into the point-slope formula.

mikezack123 · Answer

@AlwaystheBookworm ... OH yeah! lol

anonymous · Answer

@MikeZack123 lol if you're still having trouble with it, let me know and I'd be happy to help.

mikezack123 · Answer

@AlwaystheBookworm i got B... is that right?

anonymous · Answer

remember that to get the slope of the perpendicular line you need to inverse opposite. so inverse the fraction or number into a fraction and put the opposite sign

mikezack123 · Answer

@melody16  i dont get what youre saying... the answer is not b?

anonymous · Answer

She means that once you solve the equation regularly, you have to find the inverse.

anonymous · Answer

I am just saying, for future reference. alwaysthebookworm explained what i meant

mikezack123 · Answer

... im confused i dont get why you are saying that, you didnt have to solve the equation in this problem so.....

whpalmer4 · Answer

(-1, 3) and perpendicular to y = -1/3x + 7.

Okay, the slope of the original line is -1/3 because it is in slope-intercept form:
$$y = mx+b$$ where $m$ is the slope.

We need to find the slope of a perpendicular line.  If you have a slope $m$ and need to find a perpendicular slope $p$, you can find it by evaluating $p = -1/m$.

Our perpendicular slope will be $p = -1/(-1/3) = -1 * (3/-1) = -3/-1 = 3$

As a check, the product of two perpendicular slopes is -1
3 * (-1/3) = -3/3 = -1.  So far so good.

we know our perpendicular line has to go through point (-1,3) and have slope 3.  We'll use the point-slope equation for a line with known slope going through a point $(x_0,y_0)$:
$$y-y_0 = m(x-x_0)$$ (note the $m$ here is going to be our perpendicular slope, not the slope from the original line)
$$y -3 = 3(x-(-1))$$rearrange to get in slope-intercept form
$$y = 3x +6$$

mikezack123 · Answer

thanks to all of you! :)

mikezack123 · Answer

i wish i could give you ALL medals :(