Question

2x + 2y = 30 x.y = 54

Answer 1

Resposta:

{ 2x + 2y = 30  ==>x+y=15  (i)

{ x*y = 54  ==>x=54/y (ii)

(ii)  em (i)

54/y+y=15

tudo vezes y

54 +y²=15y

y²-15y+54=0

y'=[15+√(225-216)]/2 =(15+3)/2=9

y''=[15-√(225-216)]/2 =(15-3)/2=6

Se y=9 ==>x=54/9 = 6

Se y=6 ==>x=54/6)=9

Resposta : (x,y) = {(6,9) , (9 ,6)}