SOLUTION: Write the equation of the line through (2,5) and (-1,11) in the slope intercept form (y=mx+b)

Algebra ->  Graphs -> SOLUTION: Write the equation of the line through (2,5) and (-1,11) in the slope intercept form (y=mx+b)      Log On


   

Question 171404: Write the equation of the line through (2,5) and (-1,11) in the slope intercept form (y=mx+b)
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=%2811-5%29%2F%28-1-2%29 Plug in y%5B2%5D=11, y%5B1%5D=5, x%5B2%5D=-1, and x%5B1%5D=2


m=%286%29%2F%28-1-2%29 Subtract 5 from 11 to get 6


m=%286%29%2F%28-3%29 Subtract 2 from -1 to get -3


m=-2 Reduce


So the slope of the line that goes through the points and is m=-2


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


y-5=-2x%2B-2%28-2%29 Distribute


y-5=-2x%2B4 Multiply


y=-2x%2B4%2B5 Add 5 to both sides.


y=-2x%2B9 Combine like terms.


y=-2x%2B9 Simplify


So the equation that goes through the points and is y=-2x%2B9


Notice how the graph of y=-2x%2B9 goes through the points and . So this visually verifies our answer.
Graph of y=-2x%2B9 through the points and