Question

Sistema de eqaução ! Me ajudem á resolver , por favor ! Obrigado ...

 

a)

 5 x + 2 y = 6

-2 x -   y   = 3

 

b)

  x = 5 y - 2

-3x+7y=14

Answer 1

$a) \left \{ {{5x + 2y= 6} \atop {-2x - y = 3}} \right. \\ \\ \left \{ {{5x + 2y = 6} \atop {-4x -2y = 6}} \right. \\ \\ \left \{ {{5x = 6} \atop {-4x = 6 }} \right. \\ \\ x^ = 12 \\ \\ 5(12) + 2y = 6 \\ 60 + 2y = 6 \\ 2y = 6 - 60 \\ 2y = 54 \\ y = \frac{54}{2} \\ y = 27$

$b) \left \{ {{x-5y = -2} \atop {-3x +7y = 14}} \right. \\ \\ \left \{ {{3x - 15y = -6} \atop {-3x +7y = 14}} \right. \\ \\ \left \{ {{-15y = -6} \atop {7y = 14}} \right. \\ \\ 8y = 8 \\ y = \frac{8}{8} \\ y = 1 \\ \\ x - 5 (1) = -2 \\ x -5 = -2 \\ x -2 + 5 \\ x = 3$

Answer 2

Olá
  
5X+2Y=6-----------    5X+2Y=6
-2X-Y=3   (X2)------ -4X-2Y=6
---------------------------X=12
---------------------------5X+2.y=6
________________5.12-2y=6
                             60-6=2y
----------------------------- 54=2y
________________y=27
  

 B)X-5Y=-2    X3----- 3X-15Y=-6
   -3X+7Y=14---------3X+7Y=14
   ------------------------ 8Y=8
------------------------------Y=1
 X-5.1=-2
 X=-2+5
 X=3