6ab/6ab-6a^2 при a=4 b=6 6a/4a^2-b^2-3/2a+b при a=5 b=5
1) =6*4*6/6*4*6-6*4^2=1-575= -574 2)6*5/4*5^2-5^2-3/25+5=
=30-10000-48+2000= -8018