Question

ENCONTRE O CONJUNTO DE SOLUÇÕES DOS SISTEMAS DE ESQUAÇÕES
a) {2x+5y=13}
{-2x.7y=23}
b) {7m-2n= -6}
{5m+2n=6}
c) {-1=-a-b}
{-5=-a+b}
d) {-x+4y= -6}
{2x-4y= -6}

Answer 1

a) {2x+5y=13}
    {-2x+7y=23}
          12y = 36 ==> y = 3

2x = 13 - 5y ==> 2x = 13-5.(3)==> 2x = 13-15==> 2x= - 2 ==> x = - 1
=====================================================
b) {7m-2n= -6}
    {5m+2n=6}
       12m = 12 ==> m = 1

2n = 6 - 5m==> 2n = 6-5(1)==> 2n= 6-5==> 2n = 1==> n = 1/2
==================================================
c) {-1=-a-b}
    {-5=-a+b}
      - 6 = -2a(-1)==> 6= 2a ==> a = 3

b = - a + 1==> b = - 3 + 1 ==> b = - 2
====================================================
d) {-x+4y= -6}
    {2x-4y= -6}
       x = - 12

4y = - 6 + x==> 4y= - 6 -12==> 4y= - 18 ==> y = - 18/4