SOLUTION: I have a graph which shows a line with plotted points at (-5,-5) and (4,-3) and am asked to "Find an equation of the line."

Algebra ->  Graphs -> SOLUTION: I have a graph which shows a line with plotted points at (-5,-5) and (4,-3) and am asked to "Find an equation of the line."      Log On


   

Question 174350: I have a graph which shows a line with plotted points at (-5,-5) and (4,-3) and am asked to "Find an equation of the line."
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=%28-3--5%29%2F%284--5%29 Plug in y%5B2%5D=-3, y%5B1%5D=-5, x%5B2%5D=4, and x%5B1%5D=-5


m=%282%29%2F%284--5%29 Subtract -5 from -3 to get 2


m=%282%29%2F%289%29 Subtract -5 from 4 to get 9


So the slope of the line that goes through the points and is m=2%2F9


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=%282%2F9%29%28x--5%29 Plug in m=2%2F9, x%5B1%5D=-5, and y%5B1%5D=-5


y--5=%282%2F9%29%28x%2B5%29 Rewrite x--5 as x%2B5


y%2B5=%282%2F9%29%28x%2B5%29 Rewrite y--5 as y%2B5


y%2B5=%282%2F9%29x%2B%282%2F9%29%285%29 Distribute


y%2B5=%282%2F9%29x%2B10%2F9 Multiply


y=%282%2F9%29x%2B10%2F9-5 Subtract 5 from both sides.


y=%282%2F9%29x-35%2F9 Combine like terms. note: If you need help with fractions, check out this solver.


y=%282%2F9%29x-35%2F9 Simplify


So the equation that goes through the points and is y=%282%2F9%29x-35%2F9