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3 votes
Solve each system algebraically 3x+6y=-6 5x-2y=14 Help!!

User UnionP
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2 Answers

2 votes

\left \{ {{3x+6y=-6} \atop  *3} \right. \\\\ \left \{ {{3x+6y=-6} \atop {15x-6y=42}} \right.\\\+-----\\Addition\ method\\\\ 18x=36\ \ \ | divide\ by\ 18\\\\x=2\\\\2y=5x-14\\\\ y=(5x-14)/(2)=(5*2-14)/(2) =(10-14)/(2)=-2\\\\Solution\\ \left \{ {{y=-2} \atop {x=2}} \right.
User Eric Guan
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7.0k points
5 votes
If you multiply the second equation by 3, it becomes:

15x - 6y = 42

Then add the two equations together:

3x + 6y = -6
15x - 6y = 42
+

18x = 36
x = 2

substitute x back into the first equation:

3(2)+6y = -6
6 + 6y = -6
6y = -12
y = -2

So x=2,y=-2
User Zini
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