Answer:
2
+ 2
Step-by-step explanation:
= 
= 2
From the second:
2x-y=4
x=(4+y)/2 and applying this to first:
4+y+3y=12
4y+4=12
4y=8
y=2 and since x=(4+y)/2, x=3 so
x+y=2+3=5
Answer:
x=0
Step-by-step explanation:
10(x-2)=-20
10x-20=-20
add 20 on both sides.
10x=0
10 times 0 =0
x=0