SOLUTION: I have two question. write the equation of the line. Through (8,-9), perpendicular to 7x + 9y = -25 question #2 is through (-6,-7) parallel to -2x + 7y=26 Can you please Help?

Click here to see ALL problems on Equations

Question 241609: I have two question.
write the equation of the line. Through (8,-9), perpendicular to 7x + 9y = -25
question #2 is through (-6,-7) parallel to -2x + 7y=26
Can you please Help?????
Found 2 solutions by Alan3354, josmiceli:
Answer by Alan3354(69443) (Show Source):
You can put this solution on YOUR website!
write the equation of the line.
Through (8,-9), perpendicular to 7x + 9y = -25
-----
Find the slope, m, of the line by putting the eqn into slope-intercept form,
y = mx + b
That means solve for y:
7x + 9y = -25
9y = -7x - 25
y = (-7/9)x - 25/9
The slope is -7/9
------------------
The slope of lines perpendicular is the negative inverse, +9/7.
Use y = mx + b again with the point to find b:
-9 = (9/7)*8 + b
b = -9 - 72/7
b = -135/7
--> y = (9/7)x - 135/7 slope-intercept form
or 9x - 7y = 135 Standard form
-----------------
question #2 is through (-6,-7) parallel to -2x + 7y=26
Do it the same way.
If you have questions, or to check your work, email me at
gsihoutx@aol.com

Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
The rule is: if you have a line with slope = , then
ANY line perpendicular to it will have slope =
So, first you have to find the slope of your line.
Get it into the form where = slope

You can see that
Now you have to find
Divide both sides by

Divide both sides by

So, ANY line perpendicular to the given line will have this slope
The line you're looking for passes through (8,-9)
The formula is
where( , ) is the given point

Multiply both sides by

answer
Or, if you like,

I'll plot both lines