SOLUTION: Solve the system by addition. 5x – 9y = 16 x + 2y = –12

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Question 81722: Solve the system by addition.
5x – 9y = 16
x + 2y = –12

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
Solved by pluggable solver: Linear Systems by Addition
We'll solve the system:


by elimination by addition.To eliminate by addition, we need to set both coefficients of x to numbers with changed signs, i.e a and -a. Since in the second equation we have 1 as our coefficient for x, to get -5 we have to multiply all terms of the second equation by which is equal to -5.

Multiplying, we get on our second equation:


Adding both equations we get:



Since 5 and -5 cancel out, we have a linear equation:Therefore, we know that y = -4.

Plugging that in into the first equation gives us:









Therefore, our answer is:


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