So for this, you would divide the fraction by the numerator and denominator's GCF, or greatest common factor.
Starting with 18/36, the GCF would be 18 since 18 is the greatest number can go into 18 and 36. 
Next with 26/28, their GCF is 2. 
Next with 25/35, their GCF is 5. 
With 51/75, their GCF is 3. 
With 22/64, their GCF is 2. 
And lastly, 49/63 's GCF is 7. 
Also if the GCF that you know doesn't simplify all the way, you would continue reducing the fraction with more GCFs like this for 144/288:
