Question

If B is the midpoint of AC,AB=x+6 and AC=5x-6 then what is BC

Answer 1

Look at the picture.

$\overline{BC}=\overline{AC}-\overline{AB} \\ \\ \Downarrow \\ \\ \overline{BC}=5x-6-(x+6)= 5x-6-x-6=4x-12$

BC is 4x-12.