Question

Resolva esse método por adiçao
2x+3y=14
X+5y=-7

Answer 1

2x+3y=14
x+5y=-7   ×(-2)


 2x+3y=14
-2x-10y=+14
     -7y = 28 --->

-7y = 28 (-1) ---> 7y = -28 ---> y = -28/7 ---> y=-4


2x+3y = 14 ---> 2x+3.(-4) = 14 ---> 2x-12=14 ---> 2x = 14+12 ---> 2x = 26 --->

x = 26/2 ---> x=13



S = {13 ; -4}

Answer 2

 2x + 3y = 14        (1)
  x + 5y = - 7         (2)

De (1)
               2x = 14 - 3y
                 x = (14 - 3y)/2     (1a)
De (2)
                 x = - 7 - 5y          (2a)
 (1a) = (2a)
                   x = x
                               (14 - 3y)/2 = - 7 - 5y
                                14 - 3y = - 14 - 10y
                               14 + 14 = - 10y + 3y
                                       28 = - 7y
                                         y = 28/(- 7)
                                                               y = - 4
Em (2a)
                x = - 7 - 5(- 4)
                   = - 7 + 20
                                                               x = 13
     SOLUÇÃO SISTEMA
                 x = 13
                 y = - 4