a)

A = { S;A;C;H;G;I;O;K;T;N;6 }

\(\frac{75.5^4+175.5^4}{20.25.125+625.75}\)

=\(\frac{3.25.5.125+7.25.625}{4.5.25.125+625.3.25}\)

=\(\frac{3+7}{4+3}\)

=\(\frac{10}{7}\)

Ta có:

A=\(^{\left(\dfrac{1}{2}+1\right).\left(\dfrac{1}{3}+1\right).\left(\dfrac{1}{4}+1\right).....\left(\dfrac{1}{99}\right)+1}\)

A= \(\dfrac{3}{2}.\dfrac{4}{3}.\dfrac{5}{4}.....\dfrac{1}{99}+1\)

A=\(\dfrac{1}{2}+1\)

A=\(\dfrac{3}{2}\)

c)

b)

a)

b)

d)