Question

Calcule o valor de X e Y no sistema:

X-Y= -4
X.Y= 21

Answer 1

olá bom dia ☺

{X-Y= - 4----> x= - 4 + y
{X.Y= 21
:
{x= -4 + y
{x.y=21
:
(-4+y).y=21
-4y+y^2=21
y^2-4y-21=0
/\= b^2-4.ac
/\= (-4)^2-4.1. (-21)
/\=16+84
/\= 100

x'= - (-4)+10/2=>14/2=>7
x"= -(-4)-10/2=> -6/2=> -3


x= - 4+y
x= -4 + 7
x= 3

x= -4 -3
x= - 7

(x1, y1)=( 3 , 7 )
(y1 ,y2)=(-7 , -3)