Answer
Consistent
All real numbers in $x$ and $y$.
Work Step by Step
$x + 2y = 4$ $(1)$
$2x + 4y=8$ $(2)$
Multiply Equation $(1)$ by 2
$2x + 4y=8$ $(1)$
$2x + 4y=8$ $(2)$
When you subtract the two equations, the equation is always true for any real value of $x$ and $y$; therefore the system is consistent.