SOLUTION: Hello, I need some help because I don't get what I am doing wrong. Here is the problem. Find an equation of the line containing the given pair of points. (-5,-9)(-1,-8) The

Algebra ->  Equations -> SOLUTION: Hello, I need some help because I don't get what I am doing wrong. Here is the problem. Find an equation of the line containing the given pair of points. (-5,-9)(-1,-8) The       Log On


   

Question 405834: Hello,
I need some help because I don't get what I am doing wrong. Here is the problem.
Find an equation of the line containing the given pair of points.
(-5,-9)(-1,-8)
The equation of the line in slope-intercept form is y=4/4x-33/4 (this is my answer)
The answer given is 1/4x-31/4.
Why? I don't get how they get 31/4.
Please help soon.
Sincerely
Demi
Found 2 solutions by stanbon, josmiceli:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Find an equation of the line containing the given pair of points.
(-5,-9)(-1,-8)
-----------------
slope = (-8--9)/(-1--5) = 1/4
----
Form y = mx+b
You have y=-9 when x = -5 and m = 1/4; solve for "b":
-9 = (1/4)(-5) + b
---
-9 = (-5/4) + b
---
(-36/4) = (-5/4) + b
---
b = -31/4
-----
Equation:
y = (1/4)x -(31/4)
========================
Cheers,
Stan H.
=============

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Using the point-slope formula
%28y+-+%28-9%29%29+%2F+%28x+-+%28-5%29%29+=+%28-8+-+%28-9%29%29+%2F+%28-1+-+%28-5%29%29
%28y+%2B+9%29+%2F+%28x+%2B+5%29+=+%28-8+%2B+9%29+%2F+%28-1+%2B+5%29
%28y+%2B+9%29+%2F+%28x+%2B+5%29+=+1%2F4
y+%2B+9+=+%281%2F4%29%2A%28x+%2B+5%29
4y+%2B+36+=+x+%2B+5
4y+=+x+-+31
y+=+%281%2F4%29%2Ax+-+31%2F4 answer
check:
does the line include the given point?
(-1,-8)
-8+=+%281%2F4%29%2A%28-1%29+-+31%2F4
-32+=+-1+-+31
-32+=+-32
You can check the other point