Question

Se x+y=15, x+z=11 e y+z=6. calcule x+y+z

Answer 1

x + y = 15 .(-1)
x + z = 11
Igual a:
-x - y = -15
x + z =  11

-y + z = -4
 y + z =  6

2z = 2
z = 1

x + z = 11
x + 1 = 11
x = 10

x + y = 15
10 + y = 15
y = 5

x + y + z = 10 + 5 + 1 = 16