Plzzz hurrry
Point Z is the incenter of triangle RST.

Answer:
Solution,
Incentre: Incentre is a point where angle bisectors of a triangle intersects.
So,SZ is an angle bisector of <BSR
<BSZ=ZSR
16=5x-9
or, -5x=-9-16
or -5x=-25
or,X=-25/-5
X=5
Hope this helps....
Good luck on your assignment...