SOLUTION: How do you determine the value of r so the line passes through each pair of points has the given slope? example. I can't figure out how to do this: (10,r),(3,4), m = -2/7

Algebra ->  Linear-equations -> SOLUTION: How do you determine the value of r so the line passes through each pair of points has the given slope? example. I can't figure out how to do this: (10,r),(3,4), m = -2/7       Log On


   



Question 430313: How do you determine the value of r so the line passes through each pair of points has the given slope?
example.
I can't figure out how to do this:
(10,r),(3,4), m = -2/7
i just need to figure out how to do it so then i can do the rest by myself. Thanks

Answer by John10(297) About Me  (Show Source):
You can put this solution on YOUR website!
How do you determine the value of r so the line passes through each pair of points has the given slope?
Example.
(10,r),(3,4), m = -2/7
METHOD 1: Use the given slope and point to find the equation in standard form:
y - yo = m(x -xo)
y - 4 = (-2/7)(x - 3)
y -4 = (-2/7)x + 6/7
y = (-2/7)x + 6/7 + 4
y = (-2/7)x + 6/7 + 28/7
y = (-2/7)x + 34/7
(10,r) is the solution of above equation,we substitute it into the equation and find r:
r = (-2/7)(10) + 34/7 = -20/7 + 34/7 = 14/7 = 2
so r = 2
METHOD 2: USE Slope and two points
By slope formula:
m = (y2 -y1)/(x2-x1)
(10,r),(3,4), m = -2/7
(r-4)/(10 -3) = -2/7
r-4 = (-2/7)(7)
r -4 = -2
r = -2 + 4
r = 2
There you go! you can use any method to find r:)
John10