SOLUTION: Solve the system of equations. -3x -4y =9 9x +10y =-3

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Question 440671: Solve the system of equations.
-3x -4y =9
9x +10y =-3

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
-3x-4y=9 .............1
9x+10y=-3 .............2
Eliminate y
multiply (1)by 10
Multiply (2) by 4
-30x-40 y=90
36x+40y=-12
Add the two equations
6x=78
/6
x=13
plug value of x in (1)
-3x-4y=9
-39-4y=9
-4y=9+39
-4y=48
y=-12