Question

write the slope-intercept equation for the line that passes through (-7,6) and is perpendicular to -7x+9y=-2
please show all work

Answer 1

Use this guide right there: http://openstudy.com/users/zepp#/updates/4fa3474fe4b029e9dc34125e

And tell me if you still don't understand.

Answer 2

im still lost

Answer 3

Okay, let's transform that into the general form:
-7x+9y=-2
-7x+9y+2=0

From my tutorial, the slope of this function is \(\frac{-A}{B}=\frac{-(-7)}{9}=\frac{7}{9}\)

Now we are looking for the slope of a function that's perpendicular to this one; so we take this slope, and twist it, change its sign (In fact, reciprocal of the slope with a different sign): \(-\frac{9}{7}\)

Answer 4

Now we have a slope \(-\frac{9}{7}\) and a point (-7,6)

Let's take the slope-intercept equation: \(y=mx+b\)

Plug in the point (-7,6) and the slope

\(6=(-\frac{9}{7})(-7)+b\)
and find b.
\(6=9+b\)
\(-3=b\)

So the equation would be \(y=-\frac{9}{7}x-3\)

Answer 5

thank you, you were very helpful. I will keep some notes to help me out

Answer 6

You are very welcome! :)