Question

X+Y = 10
Y-Z = 20
Z+X = ?

find the value!!​

Answer 1

Answer:

Refers to this attachment..

Answer 2

Answer:

X+Y=10

X=10-Y ______1

and

Y-Z=20

Y-20=Z ______2

Add 1 and 2 , we have

Z+X= 10-Y+Y-20

= -10