Question

sistemas de equaçao 2 grau :
x2+y2+25
x+y= 7

Answer 1

  x2+y2=25
  x+y= 7 ==> x = 7 - y

  (7-y)2+y2=25
   49 - 14y + y^2 + y^2 = 25
    2y^2 - 14y +49 - 25 = 0
    2y^2 - 14y + 24 = 0 (:2)
    y^2 - 7y + 12= 0

    delta = (-7)^2 -4.1.12= 49 - 24 = 25

   y = 7+/- V25 = 7+/- 5
              2.1             2

y1= 7+ 5 ==> y1= 6
          2
 y2= 7- 5 ==> y2= 1
          2

 x1 = 7 - y1 ==> x1 = 7 - 6 ==> x1 = 1

 x2 = 7 - y2 ==> x2 = 7 - 1 ==> x1 = 6