Come now ! I'm sure you could unravel it if you look at it and think about it for a minute or two.
What's an angle bisector ? It's a line that splits an angle exactly in half. The two little angles on each side of it are EQUAL. Each of them is exactly half of the big angle.
So in this drawing, (3/2 x - 6) is equal to (1/4 x + 4) . Do you think you could find 'x' ?
3/2 x - 6 = 1/4 x + 4
Add 6 to each side of the equation: 3/2 x = 1/4 x + 10