SOLUTION: please help me solve this equation. solve the linear system. y=-4x+4 y=-x-5

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: please help me solve this equation. solve the linear system. y=-4x+4 y=-x-5      Log On


   

Question 473189: please help me solve this equation.
solve the linear system.
y=-4x+4
y=-x-5
Found 2 solutions by ewatrrr, MathLover1:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

finding the solution for the following linear system.

y=-4x+4

y=-x-5

  -x-5 = -4x+4

    -9 = -3x

      x = 3  and y = -8

Ordered pair (3,-8) is th esolution for this system



CHECKING our Answer***

y=-4x+4

-8 = -4*3 + 4 = -8

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
y=-4x%2B4....1
y=-x-5.....2.writ both in standard form

4x%2By=4....1
x%2By=-5.....2
Solved by pluggable solver: Solve the System of Equations by Graphing



Start with the given system of equations:


4x%2By=4

1x%2By=-5





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


4x%2By=4 Start with the given equation



1y=4-4x Subtract 4+x from both sides



1y=-4x%2B4 Rearrange the equation



y=%28-4x%2B4%29%2F%281%29 Divide both sides by 1



y=%28-4%2F1%29x%2B%284%29%2F%281%29 Break up the fraction



y=-4x%2B4 Reduce



Now lets graph y=-4x%2B4 (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+-4x%2B4%29+ Graph of y=-4x%2B4




So let's solve for y on the second equation


1x%2By=-5 Start with the given equation



1y=-5-x Subtract +x from both sides



1y=-x-5 Rearrange the equation



y=%28-x-5%29%2F%281%29 Divide both sides by 1



y=%28-1%2F1%29x%2B%28-5%29%2F%281%29 Break up the fraction



y=-x-5 Reduce





Now lets add the graph of y=-x-5 to our first plot to get:


+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+-4x%2B4%2C-x-5%29+ Graph of y=-4x%2B4(red) and y=-x-5(green)


From the graph, we can see that the two lines intersect at the point (3,-8) (note: you might have to adjust the window to see the intersection)