Question

Me ajudem nesse sistema
{x+y=15
{xy=56

Answer 1

x+y=15
xy=56
----------------
x=15-y
------------
(15-y)*y=56
15y-y²=56
y²-15y+56 (2 Grau, A=1 B=-15 C=56)
----------------
Delta= -15² -4.1.56
Delta= 225-224
Delta= 1
-------------------------
y= (+15+-1)/2
y¹= 16/2= 8
y²= 14/2= 7
-------------------------------------------------------------
x¹=15-y
x¹=15-8
x¹=7
--------------------------------------------------------
x²=15-7
x²=8
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O conjunto solução é (7,8),(8,7)

Answer 2

{x+ y=15

{x -y=56

x=15 -y

(15--y)*y=56

15y-y²=56

y²-15y+56

a=1. ∆=-15²-4.1.56

b=15. ∆=225-224

c=56. ∆=1.

y=(15+/-1)

_____

2

y¹=16

___=8

2

y²= 14

____=7

2

para:

x=15-y

x=15-8

x=7.

para:

x=15-7

x=8.

s{(7,8);(8,7)}.