SOLUTION: Identify the system of equations which has no solution. 5x + 2y = 4 2x – 2y = 10 –x = 3y + 1 x = 3y – 1 x – 2y = –6 2x = 4y – 12 x = 2y – 1 2x = 4y

Algebra ->  Inequalities -> SOLUTION: Identify the system of equations which has no solution. 5x + 2y = 4 2x – 2y = 10 –x = 3y + 1 x = 3y – 1 x – 2y = –6 2x = 4y – 12 x = 2y – 1 2x = 4y      Log On


   



Question 418609: Identify the system of equations which has no solution.
5x + 2y = 4
2x – 2y = 10

–x = 3y + 1
x = 3y – 1

x – 2y = –6
2x = 4y – 12

x = 2y – 1
2x = 4y

Found 2 solutions by MathLover1, richard1234:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
Identify the system of equations which has no solution.
1.
5x+%2B2y+=+4
2x+-2y+=+10


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



Start with the given system of equations:


5x%2B2y=4

2x-2y=10





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


5x%2B2y=4 Start with the given equation



2y=4-5x Subtract 5+x from both sides



2y=-5x%2B4 Rearrange the equation



y=%28-5x%2B4%29%2F%282%29 Divide both sides by 2



y=%28-5%2F2%29x%2B%284%29%2F%282%29 Break up the fraction



y=%28-5%2F2%29x%2B2 Reduce



Now lets graph y=%28-5%2F2%29x%2B2 (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+%28-5%2F2%29x%2B2%29+ Graph of y=%28-5%2F2%29x%2B2




So let's solve for y on the second equation


2x-2y=10 Start with the given equation



-2y=10-2x Subtract 2+x from both sides



-2y=-2x%2B10 Rearrange the equation



y=%28-2x%2B10%29%2F%28-2%29 Divide both sides by -2



y=%28-2%2F-2%29x%2B%2810%29%2F%28-2%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+%28-5%2F2%29x%2B2%2Cx-5%29+ Graph of y=%28-5%2F2%29x%2B2(red) and y=x-5(green)


From the graph, we can see that the two lines intersect at the point (2,-3) (note: you might have to adjust the window to see the intersection)


2.
-x+=3y+%2B+1
x+=3y-1

-x+-3y+=1
x+-3y=-1



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



Start with the given system of equations:


-x-3y=1

1x-3y=-1





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


-x-3y=1 Start with the given equation



-3y=1%2Bx Add +x to both sides



-3y=%2Bx%2B1 Rearrange the equation



y=%28%2Bx%2B1%29%2F%28-3%29 Divide both sides by -3



y=%28%2B1%2F-3%29x%2B%281%29%2F%28-3%29 Break up the fraction



y=%28-1%2F3%29x-1%2F3 Reduce



Now lets graph y=%28-1%2F3%29x-1%2F3 (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+%28-1%2F3%29x-1%2F3%29+ Graph of y=%28-1%2F3%29x-1%2F3




So let's solve for y on the second equation


1x-3y=-1 Start with the given equation



-3y=-1-x Subtract +x from both sides



-3y=-x-1 Rearrange the equation



y=%28-x-1%29%2F%28-3%29 Divide both sides by -3



y=%28-1%2F-3%29x%2B%28-1%29%2F%28-3%29 Break up the fraction



y=%281%2F3%29x%2B1%2F3 Reduce





Now lets add the graph of y=%281%2F3%29x%2B1%2F3 to our first plot to get:


Graph of y=%28-1%2F3%29x-1%2F3(red) and y=%281%2F3%29x%2B1%2F3(green)


From the graph, we can see that the two lines intersect at the point (-1,0) (note: you might have to adjust the window to see the intersection)



3.
x+%2B2y+=+-6
2x=4y+-12

x+%2B2y+=+-6
2x-4y=+-12


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



Start with the given system of equations:


1x-2y=-6

2x-4y=-12





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-2y=-6 Start with the given equation



-2y=-6-x Subtract +x from both sides



-2y=-x-6 Rearrange the equation



y=%28-x-6%29%2F%28-2%29 Divide both sides by -2



y=%28-1%2F-2%29x%2B%28-6%29%2F%28-2%29 Break up the fraction



y=%281%2F2%29x%2B3 Reduce



Now lets graph y=%281%2F2%29x%2B3 (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+%281%2F2%29x%2B3%29+ Graph of y=%281%2F2%29x%2B3




So let's solve for y on the second equation


2x-4y=-12 Start with the given equation



-4y=-12-2x Subtract 2+x from both sides



-4y=-2x-12 Rearrange the equation



y=%28-2x-12%29%2F%28-4%29 Divide both sides by -4



y=%28-2%2F-4%29x%2B%28-12%29%2F%28-4%29 Break up the fraction



y=%281%2F2%29x%2B3 Reduce





Now lets add the graph of y=%281%2F2%29x%2B3 to our first plot to get:


+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+%281%2F2%29x%2B3%2C%281%2F2%29x%2B3%29+ Graph of y=%281%2F2%29x%2B3(red) and y=%281%2F2%29x%2B3(green)


From the graph, we can see that the two lines are identical (one lies perfectly on top of the other) and intersect at all points of both lines. So there are an infinite number of solutions and the system is dependent.


4.
x+=2y+-1
2x=4y+

x+-2y=+-1
2x-4y=0+




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



Start with the given system of equations:


1x-2y=-1

2x-4y=0





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-2y=-1 Start with the given equation



-2y=-1-x Subtract +x from both sides



-2y=-x-1 Rearrange the equation



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



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



y=%281%2F2%29x%2B1%2F2 Reduce



Now lets graph y=%281%2F2%29x%2B1%2F2 (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+%281%2F2%29x%2B1%2F2%29+ Graph of y=%281%2F2%29x%2B1%2F2




So let's solve for y on the second equation


2x-4y=0 Start with the given equation



-4y=0-2x Subtract 2+x from both sides



-4y=-2x%2B0 Rearrange the equation



y=%28-2x%2B0%29%2F%28-4%29 Divide both sides by -4



y=%28-2%2F-4%29x%2B%280%29%2F%28-4%29 Break up the fraction



y=%281%2F2%29x%2B0 Reduce





Now lets add the graph of y=%281%2F2%29x%2B0 to our first plot to get:


Graph of y=%281%2F2%29x%2B1%2F2(red) and y=%281%2F2%29x%2B0(green)


From the graph, we can see that the two lines are parallel and will never intersect. So there are no solutions and the system is inconsistent.



so, number 4. is your answer

Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Instead of the extremely verbose yet tedious solution the other tutor posted using the pluggable solvers, we can determine which system has no solutions without solving each system or graphing.

First note that any two lines of different slope must intersect at exactly one point. Also, if two lines have the same slope, they are either parallel (no solution) or are the same line (infinitely many solutions). We start by finding the slopes of each line.

5x+2y = 4
2x-2y = 10

Rewriting each in y = mx + b form, we obtain:

y = (-5/2)x + 2
y = 2x - 10 Hence, this system has a solution.

Repeat the same for the other three systems:

y = (-1/3)x - 1/3
y = (1/3)x + 1/3, solution exists

y = (1/2)x + 3
y = (1/2)x + 3 These two lines are the same, so infinitely many solutions.

y = (1/2)x + 1/2
y = (1/2)x These lines are parallel and do not intersect. So, choice 4 has no solution.