Literally struggle help pls (right answer only ) giving brainliest

Answer:
PR=21
Step-by-step explanation:
make x+1 and 5x-79 equal bec it is isosceles triangle. So x+1=5x-79. Then isolate x.
4x=80
x=20
Plug x in the PR equation or PQ equation
5(20)-79
Which equals 21