SOLUTION: Solve by the elimination method. 7r-5s=-12 5r-7s=76 What is the solution of the system?

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Question 221989: Solve by the elimination method. 7r-5s=-12 5r-7s=76
What is the solution of the system?

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 7.


Distribute and multiply.


Multiply the both sides of the second equation by -5.


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. Notice how the y terms cancel out.


Simplify.


Divide both sides by to isolate .


Reduce.


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


Now go back to the first equation.


Plug in .


Multiply.


Multiply both sides by the LCD to clear any fractions.


Distribute and multiply.


Add to both sides.


Combine like terms on the right side.


Divide both sides by to isolate .


Reduce.


So the solutions are and

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