SOLUTION: I have gotten thru 4 of the 8 questions on my worksheet and am stuck with this one. the direction say to "solve each system by elimination" 12x - 7y = -10 -4x + 3y = 10 I

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Question 198012: I have gotten thru 4 of the 8 questions on my worksheet and am stuck with this one. the direction say to "solve each system by elimination"
12x - 7y = -10
-4x + 3y = 10
I can't seem to get either side to cancel out.

Found 2 solutions by jim_thompson5910, josmiceli:
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 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 josmiceli(19441)   (Show Source): You can put this solution on YOUR website!


Multiply both sides of the 2nd equation by
and add the equations


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


Plug this result back in to 2nd equation





The solution is ,
check:



and



OK

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