Question

Resolva o sistema
x+y=4
x.y=-12

Answer 1

{x+y=4

{x•y=-12

{x=4—y

{(4—y)•y=-12

{------

{4y—y²=-12

{-----

{—y²+4y+12=0

∆=4²—4•(-1)•12

∆=16+48

∆=64

y' =(-4+8)/2•(-1)

y' =4/-2

y' = -2

y'' = (-4-8)/2•(-1)

y'' = -12/-2

y'' = 6

Para y=-2

x = 4—y

x = 4—(-2)

x = 4+2

x = 6

Para y=6

x = 4—y

x = 4—6

x = —2

Sol: { -2,6,6,-2 }

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