Question

Como resolver x+y=15
y+z=12
x+z=20

Answer 1

x+y=15

x=15-y

y+z=12
x+z=20

y+z=12
15-y+z=20

y+z=12
-y+z=5

2z=12+5

2z=17

z=17/2

y+z=12

y=12-17/2

y=24-17/2

y=7/2


x=15-y

x=15-7/2

x=30-7/2

x=23/2


espero ter ajudado!