Can someone answer these 2 please and thank you

Find the difference (8ab+a+2) - (3ab+6)

What are the excluded values? m+5/mn+3m

What is the sum of the geometric series in which a1 = 7, r = 3, and an = 1,701? hint: cap s sub n equals start fraction a sub one left parenthesis one minus r to the power of n end power right parenthesis over one minus r end fraction comma r ≠ 1, where a1 is the first term and r is the common ratio