Question

Resolva Os Sistemas

Lembrando Que Essas Contas Vai Precisar Do ABC É Delta


A) (x+y=9
     ( x.y=18






B) ( x+y=10
      (x.y=21







C) (x+y=8
      (x.y=12

Answer 1

A) (x+y=9
( x.y=18

y = 18/x
x + 18/x = 9
x² + 18 = 9x
x² - 9x + 18 = 0
------------------------
Δ = b² - 4ac
Δ = 81 - 4(1)(18)
Δ = 81 - 72
Δ = 9
-------------------------
x´ = (9 + √Δ)/2(1)
x´ = (9 + 3)/2
x´ = 6
-------------------------
x´´ = (9 - √Δ)/2(1)
x´´ = (9 - 3)/2
x´´ = 3
-----------------------------------------------------------------------------------------------------

B) ( x+y=10
(x.y=21

y = 21/x
x + 21/x = 10
x² + 21 = 10x
x² - 10x + 21 = 0
---------------------------------------
Δ = b² - 4ac
Δ = 100 - 4(1)(21)
Δ = 100 - 84
Δ = 16
---------------------------------------
x´ = (10 + √Δ)/2(1)
x´ = (10 + 4)/2
x´ = 7
---------------------------------------
x´´ = (10 - √Δ)/2(1)
x´´ = (10 - 4)/2
x´´ = 6/2
x´´ = 3
---------------------------------------

C) (x+y=8
(x.y=12

y = 12/x
x + 12/x = 8
x² -8x + 12 = 0
----------------------------------
Δ = 64 - 4(1)(12)
Δ = 64 - 48
Δ = 16
---------------------------------
x´ = (8 + √Δ)/2(1)
x´ = (8 + 4)/2
x´ = 6
---------------------------------
x´´ = (8 - √Δ)/2(1)
x´´ = (8 - 4)/2
x´´ = (8 - 4)/2
x´´ = 2