## College Algebra (10th Edition)

$a=3$
Substitute $4$ to $x$ in the give equation to obtain: $4+2a=16+a(4)-6a \\4+2a=16+4a-6a \\4+2a=16-2a$ Add $2a$ and subtract $4$ to both sides of the equation to obtain: $4+2a+2a-4=16-2a+2a-4 \\4a=12$ Divide $4$ on both sides to obtain: $a=3$