SOLUTION: Find an equation of the line having the given slope and containing the given point. m= -3,(4,8) The answer book gives the answer as -3x+20. I understand how they got the -3x

Algebra ->  Linear-equations -> SOLUTION: Find an equation of the line having the given slope and containing the given point. m= -3,(4,8) The answer book gives the answer as -3x+20. I understand how they got the -3x      Log On


   

Question 273307: Find an equation of the line having the given slope and containing the given point. m= -3,(4,8)
The answer book gives the answer as -3x+20.
I understand how they got the -3x because the question says the m=-3. The formula is y=mx+b. How did they get the +20? Can you show me how?
Thank you
jpa
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


through (4, 8)

Use the point-slope form of the equation of a line to derive the desired equation:




where are the coordinates of the given point and is the slope of the given line.

So:



Simplification is left as an exercise for the student.

John