First, draw and label a rough sketch of an isosceles triangle. Now put in the values of pq=2x+3 and pr=9x-11
You know that the triangle is isosceles, therefore, the sides pq and pr are identical.
Now, make the equations equal to each other to find the value of x.
2x+3=9x-11
3+11=9x-2x
14=7x
14/7=x
2=x
Therefore the value of x=2.
Hope I helped :)