Question

RESOLVA OS SISTEMAS :
{X + 2Y = 9 }
{2X - Y = 8}

{4Y + X = 11 }
{Y + X = 8}

{X - Y= 5 }
{X + Y = 7}

Answer 1

  X + 2Y = 9 
2X - Y = 8(2)


  X + 2Y = 9 
4X - 2Y = 16
      5x = 25 ===> x = 5
==========================================
  X + 2Y = 9 ==> 2y = 9-x ==> 2y= 9-5==> 2y=4==> y= 2
================================================
B)  4Y + X = 11 
       Y + X = 8(-1)

 4Y + X = 11 
  -Y - X = -8
      3y = 3 ==> y = 1
====================================================
  Y + X = 8 ==> y = 8 - x ==> y = 8 - 1==> y = 7
====================================================
c) X - Y= 5 
   X + Y = 7
      2x = 12
       x = 6
=================================================
 x + y = 7 ==> y = 7 - x ==> y = 7 - 6 ==> y = 1