Respostas

  • Usuário do Brainly
2014-08-07T20:21:12-03:00
2x+2y=18
x+y=9
x=y-9

S=xy
S=(y-9).y
S=y²-9y
S'=2y-9
2y=9
~~>y=4,5
~~> x=4,5
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