In isosceles pqr with base , pq = 2x + 3, and pr = 9x - 11. what is the value of x?

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 :)