ANSWER
A. 8x=16
EXPLANATION
The given equations are:
1st equation: y=2x
2nd equation: 2x+3y=16
We substitute the first equation into the second equation to get:
2x+3(2x)=16
This implies that:
2x+6x=16
We combine like terms to get:
8x=16
The correct choice is A. 8x=16