SOLUTION: Given the points (2, -5) and ( -1, 4). Find the Slope and Y-intercept? Find the equation of the line? Please Thank you

Algebra ->  Linear-equations -> SOLUTION: Given the points (2, -5) and ( -1, 4). Find the Slope and Y-intercept? Find the equation of the line? Please Thank you      Log On


   

Question 177464: Given the points (2, -5) and ( -1, 4).
Find the Slope and Y-intercept?
Find the equation of the line? Please Thank you
Found 2 solutions by jim_thompson5910, stanbon:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

First let's find the slope of the line through the points and


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.


m=%284--5%29%2F%28-1-2%29 Plug in y%5B2%5D=4, y%5B1%5D=-5, x%5B2%5D=-1, and x%5B1%5D=2


m=%289%29%2F%28-1-2%29 Subtract -5 from 4 to get 9


m=%289%29%2F%28-3%29 Subtract 2 from -1 to get -3


m=-3 Reduce


So the slope of the line that goes through the points and is m=-3


Now let's use the point slope formula:


y-y%5B1%5D=m%28x-x%5B1%5D%29 Start with the point slope formula


y--5=-3%28x-2%29 Plug in m=-3, x%5B1%5D=2, and y%5B1%5D=-5


y%2B5=-3%28x-2%29 Rewrite y--5 as y%2B5


y%2B5=-3x%2B-3%28-2%29 Distribute


y%2B5=-3x%2B6 Multiply


y=-3x%2B6-5 Subtract 5 from both sides.


y=-3x%2B1 Combine like terms.


y=-3x%2B1 Simplify


So the equation that goes through the points and is y=-3x%2B1


Notice how the graph of y=-3x%2B1 goes through the points and . So this visually verifies our answer.
Graph of y=-3x%2B1 through the points and

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Given the points (2, -5) and ( -1, 4).
Find the Slope and Y-intercept?
slope = (4--5)/(-1-2) = 9/-3 = -3
----
intercept: 4 = -3*-1 + b
b = 1
-------
Find the equation of the line?
y = -3x + 1
==================
Cheers,
Stan H.