SOLUTION: What is the equations by graphing y=-x-1 y=x-7

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Question 941749: What is the equations by graphing
y=-x-1
y=x-7
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

y=-x-1
y=x-7
----------------
x%2By=-1
-x%2By=-7
----------------

Solved by pluggable solver: Solve the System of Equations by Graphing



Start with the given system of equations:


1x%2By=-1

-x%2By=-7





In order to graph these equations, we need to solve for y for each equation.




So let's solve for y on the first equation


1x%2By=-1 Start with the given equation



1y=-1-x Subtract +x from both sides



1y=-x-1 Rearrange the equation



y=%28-x-1%29%2F%281%29 Divide both sides by 1



y=%28-1%2F1%29x%2B%28-1%29%2F%281%29 Break up the fraction



y=-x-1 Reduce



Now lets graph y=-x-1 (note: if you need help with graphing, check out this solver)



+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+-x-1%29+ Graph of y=-x-1




So let's solve for y on the second equation


-x%2By=-7 Start with the given equation



1y=-7%2Bx Add +x to both sides



1y=%2Bx-7 Rearrange the equation



y=%28%2Bx-7%29%2F%281%29 Divide both sides by 1



y=%28%2B1%2F1%29x%2B%28-7%29%2F%281%29 Break up the fraction



y=x-7 Reduce





Now lets add the graph of y=x-7 to our first plot to get:


+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+-x-1%2Cx-7%29+ Graph of y=-x-1(red) and y=x-7(green)


From the graph, we can see that the two lines intersect at the point (3,-4) (note: you might have to adjust the window to see the intersection)