Question

São dadas as igualdades 2x-y+3z=34 e x+3y+z=-12. quando z =2,qual é o valor de x+y

Answer 1

2x-y+3.2=34
2x-y+6=34
2x-y= 34-6
2x-y= 28

x+3y+2=-12
x+3y= -12-2
x+3y=-14

2x-y=28
x+3y=-14 (-2)

2x-y=28
-2x-6y=28
-7y= 56
y= -56/7

x+3y= -14
x+3.-56/7= -14
x-168/7= -14
7x-168=98
7x= 98+168
7x= 266
x= 266/7

266/7-56/7= 210/7=30