a)

Cạnh hình vuông là:

\(\sqrt{25}=5\left(cm\right)\)

Chu vi hình vuông là:

\(5.4=20\left(cm\right)\)

b)

Cạnh hình vuông là:

\(48:4=12\left(m\right)\)

Diện tích hình vuông là:

\(12.12=144\left(m^2\right)\)

c)

\(-\dfrac{3}{5}.\dfrac{2}{7}+-\dfrac{3}{5}.\dfrac{5}{7}-\dfrac{-13}{5}\\ =-\dfrac{3}{5}\left(\dfrac{2}{7}+\dfrac{5}{7}\right)+\dfrac{13}{5}\\ =-\dfrac{3}{5}.1+\dfrac{13}{5}\\ =-\dfrac{3}{5}+\dfrac{13}{5}\\ =\dfrac{13-3}{5}\\ =\dfrac{10}{5}\\ =2\)

d)

\(\dfrac{8}{15}.\dfrac{-13}{27}+\dfrac{8}{15}.\dfrac{-14}{27}+1\dfrac{2}{3}\\ =\dfrac{8}{15}\left(-\dfrac{13}{27}-\dfrac{14}{27}\right)+\dfrac{5}{3}\\ =\dfrac{8}{15}.-1+\dfrac{5}{3}\\ =-\dfrac{8}{15}+\dfrac{5.5}{15}\\ =\dfrac{25-8}{15}\\ =\dfrac{17}{15}\)