SOLUTION: I was given two points on finding an equation in slope-intercept form through (8, -1) and (4, 3). Here is what I have done and I have no clue if it is right or not. m=3-(-1)/4-8

Algebra ->  Linear-equations -> SOLUTION: I was given two points on finding an equation in slope-intercept form through (8, -1) and (4, 3). Here is what I have done and I have no clue if it is right or not. m=3-(-1)/4-8      Log On


   

Question 238599: I was given two points on finding an equation in slope-intercept form through (8, -1) and (4, 3). Here is what I have done and I have no clue if it is right or not.
m=3-(-1)/4-8
m=4/-4
m= -1
y-3 = -1 (x-4)
y-3 = -1x -4
y = -1x + 4 + 1
y = -1x + 5
would this be the equation in slope- intercept form?
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


Note: is the first point . So this means that x%5B1%5D=8 and y%5B1%5D=-1.
Also, is the second point . So this means that x%5B2%5D=4 and y%5B2%5D=3.


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


m=%283--1%29%2F%284-8%29 Plug in y%5B2%5D=3, y%5B1%5D=-1, x%5B2%5D=4, and x%5B1%5D=8


m=%284%29%2F%284-8%29 Subtract -1 from 3 to get 4


m=%284%29%2F%28-4%29 Subtract 8 from 4 to get -4


m=-1 Reduce


So the slope of the line that goes through the points and is m=-1


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--1=-1%28x-8%29 Plug in m=-1, x%5B1%5D=8, and y%5B1%5D=-1


y%2B1=-1%28x-8%29 Rewrite y--1 as y%2B1


y%2B1=-1x%2B-1%28-8%29 Distribute


y%2B1=-1x%2B8 Multiply


y=-1x%2B8-1 Subtract 1 from both sides.


y=-1x%2B7 Combine like terms.


y=-x%2B7 Simplify


So the equation that goes through the points and is y=-x%2B7


Notice how the graph of y=-x%2B7 goes through the points and . So this visually verifies our answer.
Graph of y=-x%2B7 through the points and