What is the value of x? Triangle RST

We can see that
angle(C)=angle(B)
Since, both angles are equal
so, this is isosceles triangle
and in isosceles triangle , two sides are equal
so, we get
[tex]AC=AB[/tex]
now, we are given
[tex]AC=x+9[/tex]
[tex]AB=2x-8[/tex]
now, we can set them equal
[tex]x+9=2x-8[/tex]
we can solve for x
Add both sides 8
[tex]x+9+8=2x-8+8[/tex]
[tex]x+17=2x[/tex]
Subtract both sides by x
[tex]x+17-x=2x-x[/tex]
[tex]17=x[/tex]
So, we get
[tex]x=17[/tex]..............Answer