SOLUTION: Write the slope - intercept equation for the line that passes through (-1,-3) and (-2,5)

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Question 628257: Write the slope - intercept equation for the line that passes through (-1,-3) and (-2,5)
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=-1 and y%5B1%5D=-3.
Also, is the second point . So this means that x%5B2%5D=-2 and y%5B2%5D=5.


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


m=%285--3%29%2F%28-2--1%29 Plug in y%5B2%5D=5, y%5B1%5D=-3, x%5B2%5D=-2, and x%5B1%5D=-1


m=%288%29%2F%28-2--1%29 Subtract -3 from 5 to get 8


m=%288%29%2F%28-1%29 Subtract -1 from -2 to get -1


m=-8 Reduce


So the slope of the line that goes through the points and is m=-8


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--3=-8%28x--1%29 Plug in m=-8, x%5B1%5D=-1, and y%5B1%5D=-3


y--3=-8%28x%2B1%29 Rewrite x--1 as x%2B1


y%2B3=-8%28x%2B1%29 Rewrite y--3 as y%2B3


y%2B3=-8x%2B-8%281%29 Distribute


y%2B3=-8x-8 Multiply


y=-8x-8-3 Subtract 3 from both sides.


y=-8x-11 Combine like terms.


So the equation that goes through the points and is y=-8x-11

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