x+y=94 -> y=94-x
x-y=12
Substitute: x-(94-x)=12
Distribute: x-94+x=12
Simplify: 2x=106
Solve: x=53
Plug x back into equation
x-y=12
53-y=12
y=41
x= 53, y=41
Second Question:
8+x=y
x+y = 66
Substitute: x+8+x =66
Simplify: 2x+8 =66
Solve : x=29
Plug x back into equation
x+y=66
29+y=66
y = 37
x=29, y=37
