1/(√7-1)-1/(√7-3)=a+b√c

[√7-3-(√7-1)]/(10-4√7)=a+b√c

(1-3)/(10-4√7)=a+b√c

-2/2(5-2√7)=a+b√c

-1/(5-2√7)=a+b√c

-(5+2√7)/(25-28)=a+b√c

-(5+2√7)/-3=a+b√c

5/3+2/3√7=a+b√c

a=5/3 b=⅔ c=√7/3

Is this correct

very good until your last step

5/3+2/3√7=a+b√c
a=5/3 b=⅔ c=7