a) √25+√36-√49=5+6-7=11-7=4
b) √100·√16-√144=10·4-12=40-12=28
c) 3·√225+12√121-√169=3·15+12·11-13=45+132-13=177-13=164
d) 5√81-√64·√196+2√100=5·9-8·14+2·10=45-112+20=-67+20=-47
e)√576-√625+√729-√841+√900=24-25+27-29+30=-1+27-29+30=26-29+30=-3+30=27
f) √6400-√2025+√3364-√5184-√441=80-45+58-72-21=35+58-72-21=93-72-21=21-21=0