1)
= (a^(-7/4))*(a^2-1)/( (a^(-3/4)) *(a-1) )=(a^(-7/4-(-3/4))*(a+1)(a-1)/(a-1)=(a^(-1))*(a+1)=(a+1)/a
2) предположительно, первое слагаемое числителя b^5/4, а не b^5/7,
тогда
=( (b^(1/4)) * (b+2+b^(-1) ) / ( (b^(1/4)) * (b^(1/2)+b^(-1/2) ) ) = ( b+2+b^(-1) ) / ( b^(1/2)+b^(-1/2) ) =( b^(1/2)+b^(-1/2) )^2 / ( b^(1/2)+b^(-1/2) )=b^(1/2)+b^(-1/2)