SOLUTION: Solve the following system of equations, and check: 2x+3y=-4 5x+2y=1

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Question 198423: Solve the following system of equations, and check:
2x+3y=-4
5x+2y=1

Found 2 solutions by jim_thompson5910, m.keenan:
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!

Start with the given system of equations:



Multiply the both sides of the first equation by -2.


Distribute and multiply.


Multiply the both sides of the second equation by 3.


Distribute and multiply.


So we have the new system of equations:



Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:





Group like terms.


Combine like terms.


Simplify.


Divide both sides by to isolate .


Reduce.


------------------------------------------------------------------


Now go back to the first equation.


Plug in .


Multiply.


Add to both sides.


Combine like terms on the right side.


Divide both sides by to isolate .


Reduce.


So the solutions are and .


Which form the ordered pair .


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of (red) and (green)

Answer by m.keenan(1)   (Show Source): You can put this solution on YOUR website!
Solve the following system of equations, and check:
2x+3y=-4 (1)
5x+2y=1 (2) label equations
= 2x+3y=-4 (1) *2
5x+2y=1 (2) *3
=4x+6y=-8 (3)
15x+6y=3 (4) label new equations
Therefore: 4x+6y-(15x+6y)=-8-3
=4x+6y-15x-6y=-11
= -11x= =11
= x=1
Now we can sub x=1 back into any labelled equation.
2(1) +3y=-4
=3y=-6
y=-2

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