The answer is 0 < x < infinity
The second result is more precise because it's in millilitre,so if the first were to be fully precise,it should have been 78.6 cm.
Hope this helps!
X + y = 8
x - y = 12
--------------add
2x = 20
x = 20/2
x = 10
x + y = 8
10 + y = 8
y = 8 - 10
y = -2
ur numbers are 10 and -2
If we multiply the top equation by -4 we can get rid of the x so:
-4x+20y=-12
4x-4y=12
Add these up
16y=0
Y=0
X=3