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Murljashka [212]
3 years ago
15

If 3x + 5y = 42 and 9x +7y = 78, then x + y = ?

Mathematics
1 answer:
kumpel [21]3 years ago
8 0
3x+5y=42

9x+7y=78

adding above equation

12x+12y=120

x+y=10
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