а) 5у/20+(4у-8)/20=(9у+12)/20
б) (4х-2)/6-(х+2)/6=3х-4/6
в) -2а+2b/10+4a-b/10=2a+b=10
г) c+3/c^2-c/c^2=3/c^2
д) 7x-3yx/y-8y+3yx/x=7x-8y
e) mn-n^2/m^2n-mn+m^2/m^2n=m^2-n^2
