Respuesta :

Find the GCF of 88 and 24 first 

88=2*2*2*11 
24=2*2*2*3 

The GCF for 88 and 24 is 8 
The GCF for r^18 and r^13 is r^13 (because they both contain r^13 in them) 

=8r^13(11, 3) 

Hope I helped :)