garfieldslasaga garfieldslasaga
  • 22-02-2019
  • Mathematics
contestada

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

Respuesta :

janak1610
janak1610 janak1610
  • 22-02-2019
3x+5y=42

9x+7y=78

adding above equation

12x+12y=120

x+y=10
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