Answer
$x=11$
$m\angle ABC=56$
Work Step by Step
Use the definition of a bisector:
$m\angle ABD=m\angle CBD$
$4x-16=2x+6$
Subtract 2x from each side:
$4x-16-2x=2x+6-2x$
$2x-16=6$
Add 16 to each side:
$2x-16+16=6+16$
$2x=22$
Divide each side by 2:
$2x\div2=22\div2$
$x=11$
Angle Addition Postulate:
$m\angle ABC=(4x-16)+(2x+6)=6x-10=6(11)-10=66-10=56$
