Question 67614
first look at the problem closely y=2y-4
since y equals 2y. minus 4 then y has to be 4
since y+y-4=y
y=4
now enter y to the other equation if substituted to the same formula infinite many solutions will be the answer.this is wrong for this question 
8x-4y=16
8x-(4*4)=16
8x-16=16
take the minus 16 to the other side to isolate 8x
and negate the signs to it 
8x=16+16
8x=32
divide both sides to isolate x
x=4


THE ANSWER IS=(4,4)