SOLUTION: Find an equation of the line containing the given pair of points (-9,0) and (0,7)

Algebra ->  Linear-equations -> SOLUTION: Find an equation of the line containing the given pair of points (-9,0) and (0,7)      Log On


   

Question 189690: Find an equation of the line containing the given pair of points (-9,0) and (0,7)
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 and is the second point .


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


m=%287-0%29%2F%280--9%29 Plug in y%5B2%5D=7, y%5B1%5D=0, x%5B2%5D=0, and x%5B1%5D=-9


m=%287%29%2F%280--9%29 Subtract 0 from 7 to get 7


m=%287%29%2F%289%29 Subtract -9 from 0 to get 9


So the slope of the line that goes through the points and is m=7%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-0=%287%2F9%29%28x--9%29 Plug in m=7%2F9, x%5B1%5D=-9, and y%5B1%5D=0


y=%287%2F9%29%28x--9%29 Simplify


y=%287%2F9%29%28x%2B9%29 Rewrite x--9 as x%2B9


y=%287%2F9%29x%2B%287%2F9%29%289%29 Distribute


y=%287%2F9%29x%2B7 Multiply


So the equation that goes through the points and is y=%287%2F9%29x%2B7


Notice how the graph of y=%287%2F9%29x%2B7 goes through the points and . So this visually verifies our answer.
Graph of y=%287%2F9%29x%2B7 through the points and