SOLUTION: 3.4 38. Find the equation of the line through each given pair of points. Write the answer in standard form using only integers. (-1,-3), (2,-1)

Algebra ->  Linear-equations -> SOLUTION: 3.4 38. Find the equation of the line through each given pair of points. Write the answer in standard form using only integers. (-1,-3), (2,-1)       Log On


   

Question 173677This question is from textbook Elementary and intermediate
: 3.4
38. Find the equation of the line through each given pair of points. Write the answer in standard form using only integers.
(-1,-3), (2,-1)
 This question is from textbook Elementary and intermediate

Found 2 solutions by Alan3354, jojo14344:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
38. Find the equation of the line through each given pair of points. Write the answer in standard form using only integers.
(-1,-3), (2,-1)
----------
|x y +1|
|-1 -3 1| = 0
|+2 -1 1|
x*(-3 + 1) -y*(-1-2) + 1*(1+6) = 0
-2x +3y + 7 = 0
2x - 3y = 7


Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!
(-1,-3), (2,-1)
first,we find the Slope=m thru given points:
Via Slope Form:
m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29
where--->system%28y%5B2%5D=-1%2Cy%5B1%5D=-3%2Cx%5B2%5D=2%2Cx%5B1%5D=-1%29
Then,
m=%28-1-%28-3%29%29%2F%282-%28-1%29%29=%28-1%2B3%29%2F%282%2B1%29=2%2F3
Then, thru points (-1,-3): Via Slope-Intercept--->y=mx%2Bb
-3=%282%2F3%29%28-1%29%2Bb
-3=%28-2%2F3%29%2Bb
b=-3%2B%282%2F3%29=%28-9%2B2%29%2F3=-7%2F3
Then,
y=%282%2F3%29x-%287%2F3%29.--->y-%282%2F3%29x=-7%2F3
%283y-2x%29%2F3=-7%2F3-->3y-2x=3%2A%28-7%2F3%29
highlight%283y-2x%2B7=0%29
ROUND-OFF
y=1x-2--->-x%2By%2B2=0, Standard form

Thank you,
Jojo