SOLUTION: Find the equation of the line through the points (-2, 1) and (1, -4). Write the equation in standard form with only integers. Please explain how this problem was solved. Tha

Algebra ->  Graphs -> SOLUTION: Find the equation of the line through the points (-2, 1) and (1, -4). Write the equation in standard form with only integers. Please explain how this problem was solved. Tha      Log On


   

Question 63793: Find the equation of the line through the points (-2, 1) and (1, -4). Write the equation in standard form with only integers.
Please explain how this problem was solved.
Thank you!
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Find the equation of the line through the points (-2, 1) and (1, -4). Write the equation in standard form with only integers.
Please explain how this problem was solved.
;
First, find the slope (m) using the slope formula: %28y2+-+y1%29%2F%28x2+-+x1%29
:
In your problem x1 = -2; y1 = 1; x2 = 1; y2 = -4); so we have:
m = %28-4+-+1%29%2F%281+-+%28-2%29%29 = %28-4+-+1%29%2F%281+%2B+2%29
m = %28-5%29%2F%283%29%29
:
slope (m) = -(5/3):
:
Use the point/slope equation: y - y1 = m(x-x1)
y - 1 = (-5/3(x - (-2))
y - 1 = (-5/3)(x + 2)
y - 1 = (-5/3)x - (10/3)
y = (-5/3)x - (10/3) + 1
y = (-5/3)x - (10/3) + (3/3)
y = (-5/3)x - (7/3)
:
Get rid of these annoying decimals, mult eq by 3
3y = -5x - 7
:
They want it in the standard form: ax + by = c, add 5x to both sides
5x + 3y = -7
:
Check using x = -2, y = 1 as given in the original problem:
5(-2) + 3(1) =
-10 + 3 = -7
:
Could you follow this OK??